diff --git a/aws/src/main/java/org/apache/iceberg/aws/s3/signer/S3V4RestSignerClient.java b/aws/src/main/java/org/apache/iceberg/aws/s3/signer/S3V4RestSignerClient.java
index f284822161ca..cdbdfb3d869e 100644
--- a/aws/src/main/java/org/apache/iceberg/aws/s3/signer/S3V4RestSignerClient.java
+++ b/aws/src/main/java/org/apache/iceberg/aws/s3/signer/S3V4RestSignerClient.java
@@ -118,6 +118,11 @@ public String oauth2ServerUri() {
     return properties().getOrDefault(OAuth2Properties.OAUTH2_SERVER_URI, ResourcePaths.tokens());
   }
 
+  @Value.Lazy
+  public Map<String, String> optionalOAuthParams() {
+    return OAuth2Util.buildOptionalParam(properties());
+  }
+
   /** A Bearer token supplier which will be used for interaction with the server. */
   @Value.Default
   public Supplier<String> token() {
@@ -207,7 +212,13 @@ private AuthSession authSession() {
                       token,
                       expiresAtMillis(properties()),
                       new AuthSession(
-                          ImmutableMap.of(), token, null, credential(), SCOPE, oauth2ServerUri())));
+                          ImmutableMap.of(),
+                          token,
+                          null,
+                          credential(),
+                          SCOPE,
+                          oauth2ServerUri(),
+                          optionalOAuthParams())));
     }
 
     if (credentialProvided()) {
@@ -217,11 +228,22 @@ private AuthSession authSession() {
               id -> {
                 AuthSession session =
                     new AuthSession(
-                        ImmutableMap.of(), null, null, credential(), SCOPE, oauth2ServerUri());
+                        ImmutableMap.of(),
+                        null,
+                        null,
+                        credential(),
+                        SCOPE,
+                        oauth2ServerUri(),
+                        optionalOAuthParams());
                 long startTimeMillis = System.currentTimeMillis();
                 OAuthTokenResponse authResponse =
                     OAuth2Util.fetchToken(
-                        httpClient(), session.headers(), credential(), SCOPE, oauth2ServerUri());
+                        httpClient(),
+                        session.headers(),
+                        credential(),
+                        SCOPE,
+                        oauth2ServerUri(),
+                        optionalOAuthParams());
                 return AuthSession.fromTokenResponse(
                     httpClient(), tokenRefreshExecutor(), authResponse, startTimeMillis, session);
               });
diff --git a/core/src/main/java/org/apache/iceberg/rest/RESTSessionCatalog.java b/core/src/main/java/org/apache/iceberg/rest/RESTSessionCatalog.java
index a34f738c318e..96aa14b128da 100644
--- a/core/src/main/java/org/apache/iceberg/rest/RESTSessionCatalog.java
+++ b/core/src/main/java/org/apache/iceberg/rest/RESTSessionCatalog.java
@@ -179,6 +179,7 @@ public void initialize(String name, Map<String, String> unresolved) {
     OAuthTokenResponse authResponse;
     String credential = props.get(OAuth2Properties.CREDENTIAL);
     String scope = props.getOrDefault(OAuth2Properties.SCOPE, OAuth2Properties.CATALOG_SCOPE);
+    Map<String, String> optionalOAuthParams = OAuth2Util.buildOptionalParam(props);
     String oauth2ServerUri =
         props.getOrDefault(OAuth2Properties.OAUTH2_SERVER_URI, ResourcePaths.tokens());
     try (RESTClient initClient = clientBuilder.apply(props)) {
@@ -186,7 +187,8 @@ public void initialize(String name, Map<String, String> unresolved) {
           RESTUtil.merge(configHeaders(props), OAuth2Util.authHeaders(initToken));
       if (credential != null && !credential.isEmpty()) {
         authResponse =
-            OAuth2Util.fetchToken(initClient, initHeaders, credential, scope, oauth2ServerUri);
+            OAuth2Util.fetchToken(
+                initClient, initHeaders, credential, scope, oauth2ServerUri, optionalOAuthParams);
         Map<String, String> authHeaders =
             RESTUtil.merge(initHeaders, OAuth2Util.authHeaders(authResponse.token()));
         config = fetchConfig(initClient, authHeaders, props);
@@ -213,7 +215,9 @@ public void initialize(String name, Map<String, String> unresolved) {
     this.paths = ResourcePaths.forCatalogProperties(mergedProps);
 
     String token = mergedProps.get(OAuth2Properties.TOKEN);
-    this.catalogAuth = new AuthSession(baseHeaders, null, null, credential, scope, oauth2ServerUri);
+    this.catalogAuth =
+        new AuthSession(
+            baseHeaders, null, null, credential, scope, oauth2ServerUri, optionalOAuthParams);
     if (authResponse != null) {
       this.catalogAuth =
           AuthSession.fromTokenResponse(
diff --git a/core/src/main/java/org/apache/iceberg/rest/auth/OAuth2Properties.java b/core/src/main/java/org/apache/iceberg/rest/auth/OAuth2Properties.java
index e1a9181d164d..295e24519129 100644
--- a/core/src/main/java/org/apache/iceberg/rest/auth/OAuth2Properties.java
+++ b/core/src/main/java/org/apache/iceberg/rest/auth/OAuth2Properties.java
@@ -49,6 +49,12 @@ private OAuth2Properties() {}
   /** Additional scope for OAuth2. */
   public static final String SCOPE = "scope";
 
+  /** Optional param audience for OAuth2. */
+  public static final String AUDIENCE = "audience";
+
+  /** Optional param resource for OAuth2. */
+  public static final String RESOURCE = "resource";
+
   /** Scope for OAuth2 flows. */
   public static final String CATALOG_SCOPE = "catalog";
 
diff --git a/core/src/main/java/org/apache/iceberg/rest/auth/OAuth2Util.java b/core/src/main/java/org/apache/iceberg/rest/auth/OAuth2Util.java
index ad1821a3f2b6..9e36694508d9 100644
--- a/core/src/main/java/org/apache/iceberg/rest/auth/OAuth2Util.java
+++ b/core/src/main/java/org/apache/iceberg/rest/auth/OAuth2Util.java
@@ -40,6 +40,7 @@
 import org.apache.iceberg.relocated.com.google.common.base.Splitter;
 import org.apache.iceberg.relocated.com.google.common.collect.ImmutableList;
 import org.apache.iceberg.relocated.com.google.common.collect.ImmutableMap;
+import org.apache.iceberg.relocated.com.google.common.collect.ImmutableSet;
 import org.apache.iceberg.relocated.com.google.common.collect.Sets;
 import org.apache.iceberg.rest.ErrorHandlers;
 import org.apache.iceberg.rest.RESTClient;
@@ -129,18 +130,40 @@ public static String toScope(Iterable<String> scopes) {
     return SCOPE_JOINER.join(scopes);
   }
 
+  public static Map<String, String> buildOptionalParam(Map<String, String> properties) {
+    // these are some options oauth params based on specification
+    // for any new optional oauth param, define the constant and add the constant to this list
+    Set<String> optionalParamKeys =
+        ImmutableSet.of(OAuth2Properties.AUDIENCE, OAuth2Properties.RESOURCE);
+    ImmutableMap.Builder<String, String> optionalParamBuilder = ImmutableMap.builder();
+    // add scope too,
+    optionalParamBuilder.put(
+        OAuth2Properties.SCOPE,
+        properties.getOrDefault(OAuth2Properties.SCOPE, OAuth2Properties.CATALOG_SCOPE));
+    // add all other parameters
+    for (String key : optionalParamKeys) {
+      String value = properties.get(key);
+      if (value != null) {
+        optionalParamBuilder.put(key, value);
+      }
+    }
+    return optionalParamBuilder.buildKeepingLast();
+  }
+
   private static OAuthTokenResponse refreshToken(
       RESTClient client,
       Map<String, String> headers,
       String subjectToken,
       String subjectTokenType,
       String scope,
-      String oauth2ServerUri) {
+      String oauth2ServerUri,
+      Map<String, String> optionalOAuthParams) {
     Map<String, String> request =
         tokenExchangeRequest(
             subjectToken,
             subjectTokenType,
-            scope != null ? ImmutableList.of(scope) : ImmutableList.of());
+            scope != null ? ImmutableList.of(scope) : ImmutableList.of(),
+            optionalOAuthParams);
 
     OAuthTokenResponse response =
         client.postForm(
@@ -162,14 +185,16 @@ public static OAuthTokenResponse exchangeToken(
       String actorToken,
       String actorTokenType,
       String scope,
-      String oauth2ServerUri) {
+      String oauth2ServerUri,
+      Map<String, String> optionalParams) {
     Map<String, String> request =
         tokenExchangeRequest(
             subjectToken,
             subjectTokenType,
             actorToken,
             actorTokenType,
-            scope != null ? ImmutableList.of(scope) : ImmutableList.of());
+            scope != null ? ImmutableList.of(scope) : ImmutableList.of(),
+            optionalParams);
 
     OAuthTokenResponse response =
         client.postForm(
@@ -199,7 +224,29 @@ public static OAuthTokenResponse exchangeToken(
         actorToken,
         actorTokenType,
         scope,
-        ResourcePaths.tokens());
+        ResourcePaths.tokens(),
+        ImmutableMap.of());
+  }
+
+  public static OAuthTokenResponse exchangeToken(
+      RESTClient client,
+      Map<String, String> headers,
+      String subjectToken,
+      String subjectTokenType,
+      String actorToken,
+      String actorTokenType,
+      String scope,
+      String oauth2ServerUri) {
+    return exchangeToken(
+        client,
+        headers,
+        subjectToken,
+        subjectTokenType,
+        actorToken,
+        actorTokenType,
+        scope,
+        oauth2ServerUri,
+        ImmutableMap.of());
   }
 
   public static OAuthTokenResponse fetchToken(
@@ -207,10 +254,13 @@ public static OAuthTokenResponse fetchToken(
       Map<String, String> headers,
       String credential,
       String scope,
-      String oauth2ServerUri) {
+      String oauth2ServerUri,
+      Map<String, String> optionalParams) {
     Map<String, String> request =
         clientCredentialsRequest(
-            credential, scope != null ? ImmutableList.of(scope) : ImmutableList.of());
+            credential,
+            scope != null ? ImmutableList.of(scope) : ImmutableList.of(),
+            optionalParams);
 
     OAuthTokenResponse response =
         client.postForm(
@@ -227,12 +277,27 @@ public static OAuthTokenResponse fetchToken(
   public static OAuthTokenResponse fetchToken(
       RESTClient client, Map<String, String> headers, String credential, String scope) {
 
-    return fetchToken(client, headers, credential, scope, ResourcePaths.tokens());
+    return fetchToken(
+        client, headers, credential, scope, ResourcePaths.tokens(), ImmutableMap.of());
+  }
+
+  public static OAuthTokenResponse fetchToken(
+      RESTClient client,
+      Map<String, String> headers,
+      String credential,
+      String scope,
+      String oauth2ServerUri) {
+
+    return fetchToken(client, headers, credential, scope, oauth2ServerUri, ImmutableMap.of());
   }
 
   private static Map<String, String> tokenExchangeRequest(
-      String subjectToken, String subjectTokenType, List<String> scopes) {
-    return tokenExchangeRequest(subjectToken, subjectTokenType, null, null, scopes);
+      String subjectToken,
+      String subjectTokenType,
+      List<String> scopes,
+      Map<String, String> optionalOAuthParams) {
+    return tokenExchangeRequest(
+        subjectToken, subjectTokenType, null, null, scopes, optionalOAuthParams);
   }
 
   private static Map<String, String> tokenExchangeRequest(
@@ -240,7 +305,8 @@ private static Map<String, String> tokenExchangeRequest(
       String subjectTokenType,
       String actorToken,
       String actorTokenType,
-      List<String> scopes) {
+      List<String> scopes,
+      Map<String, String> optionalParams) {
     Preconditions.checkArgument(
         VALID_TOKEN_TYPES.contains(subjectTokenType), "Invalid token type: %s", subjectTokenType);
     Preconditions.checkArgument(
@@ -257,8 +323,9 @@ private static Map<String, String> tokenExchangeRequest(
       formData.put(ACTOR_TOKEN, actorToken);
       formData.put(ACTOR_TOKEN_TYPE, actorTokenType);
     }
+    formData.putAll(optionalParams);
 
-    return formData.build();
+    return formData.buildKeepingLast();
   }
 
   private static Pair<String, String> parseCredential(String credential) {
@@ -278,13 +345,17 @@ private static Pair<String, String> parseCredential(String credential) {
   }
 
   private static Map<String, String> clientCredentialsRequest(
-      String credential, List<String> scopes) {
+      String credential, List<String> scopes, Map<String, String> optionalOAuthParams) {
     Pair<String, String> credentialPair = parseCredential(credential);
-    return clientCredentialsRequest(credentialPair.first(), credentialPair.second(), scopes);
+    return clientCredentialsRequest(
+        credentialPair.first(), credentialPair.second(), scopes, optionalOAuthParams);
   }
 
   private static Map<String, String> clientCredentialsRequest(
-      String clientId, String clientSecret, List<String> scopes) {
+      String clientId,
+      String clientSecret,
+      List<String> scopes,
+      Map<String, String> optionalOAuthParams) {
     ImmutableMap.Builder<String, String> formData = ImmutableMap.builder();
     formData.put(GRANT_TYPE, CLIENT_CREDENTIALS);
     if (clientId != null) {
@@ -292,8 +363,9 @@ private static Map<String, String> clientCredentialsRequest(
     }
     formData.put(CLIENT_SECRET, clientSecret);
     formData.put(SCOPE, toScope(scopes));
+    formData.putAll(optionalOAuthParams);
 
-    return formData.build();
+    return formData.buildKeepingLast();
   }
 
   public static String tokenResponseToJson(OAuthTokenResponse response) {
@@ -394,13 +466,16 @@ public static class AuthSession {
     private volatile boolean keepRefreshed = true;
     private final String oauth2ServerUri;
 
+    private Map<String, String> optionalOAuthParams = ImmutableMap.of();
+
     public AuthSession(
         Map<String, String> baseHeaders,
         String token,
         String tokenType,
         String credential,
         String scope,
-        String oauth2ServerUri) {
+        String oauth2ServerUri,
+        Map<String, String> optionalOAuthParams) {
       this.headers = RESTUtil.merge(baseHeaders, authHeaders(token));
       this.token = token;
       this.tokenType = tokenType;
@@ -408,6 +483,7 @@ public AuthSession(
       this.credential = credential;
       this.scope = scope;
       this.oauth2ServerUri = oauth2ServerUri;
+      this.optionalOAuthParams = optionalOAuthParams;
     }
 
     /** @deprecated since 1.5.0, will be removed in 1.6.0 */
@@ -427,6 +503,25 @@ public AuthSession(
       this.oauth2ServerUri = ResourcePaths.tokens();
     }
 
+    /** @deprecated since 1.6.0, will be removed in 1.7.0 */
+    @Deprecated
+    public AuthSession(
+        Map<String, String> baseHeaders,
+        String token,
+        String tokenType,
+        String credential,
+        String scope,
+        String oauth2ServerUri) {
+      this.headers = RESTUtil.merge(baseHeaders, authHeaders(token));
+      this.token = token;
+      this.tokenType = tokenType;
+      this.expiresAtMillis = OAuth2Util.expiresAtMillis(token);
+      this.credential = credential;
+      this.scope = scope;
+      this.oauth2ServerUri = oauth2ServerUri;
+      this.optionalOAuthParams = ImmutableMap.of();
+    }
+
     public Map<String, String> headers() {
       return headers;
     }
@@ -459,6 +554,10 @@ public String oauth2ServerUri() {
       return oauth2ServerUri;
     }
 
+    public Map<String, String> optionalOAuthParams() {
+      return optionalOAuthParams;
+    }
+
     @VisibleForTesting
     static void setTokenRefreshNumRetries(int retries) {
       tokenRefreshNumRetries = retries;
@@ -471,7 +570,13 @@ static void setTokenRefreshNumRetries(int retries) {
      */
     public static AuthSession empty() {
       return new AuthSession(
-          ImmutableMap.of(), null, null, null, OAuth2Properties.CATALOG_SCOPE, null);
+          ImmutableMap.of(),
+          null,
+          null,
+          null,
+          OAuth2Properties.CATALOG_SCOPE,
+          null,
+          ImmutableMap.of());
     }
 
     /**
@@ -526,14 +631,16 @@ private OAuthTokenResponse refreshCurrentToken(RESTClient client) {
         return refreshExpiredToken(client);
       } else {
         // attempt a normal refresh
-        return refreshToken(client, headers(), token, tokenType, scope, oauth2ServerUri);
+        return refreshToken(
+            client, headers(), token, tokenType, scope, oauth2ServerUri, optionalOAuthParams);
       }
     }
 
     private OAuthTokenResponse refreshExpiredToken(RESTClient client) {
       if (credential != null) {
         Map<String, String> basicHeaders = RESTUtil.merge(headers(), basicAuthHeaders(credential));
-        return refreshToken(client, basicHeaders, token, tokenType, scope, oauth2ServerUri);
+        return refreshToken(
+            client, basicHeaders, token, tokenType, scope, oauth2ServerUri, optionalOAuthParams);
       }
 
       return null;
@@ -590,7 +697,8 @@ public static AuthSession fromAccessToken(
               OAuth2Properties.ACCESS_TOKEN_TYPE,
               parent.credential(),
               parent.scope(),
-              parent.oauth2ServerUri());
+              parent.oauth2ServerUri(),
+              parent.optionalOAuthParams());
 
       long startTimeMillis = System.currentTimeMillis();
       Long expiresAtMillis = session.expiresAtMillis();
@@ -629,7 +737,12 @@ public static AuthSession fromCredential(
       long startTimeMillis = System.currentTimeMillis();
       OAuthTokenResponse response =
           fetchToken(
-              client, parent.headers(), credential, parent.scope(), parent.oauth2ServerUri());
+              client,
+              parent.headers(),
+              credential,
+              parent.scope(),
+              parent.oauth2ServerUri(),
+              parent.optionalOAuthParams());
       return fromTokenResponse(client, executor, response, startTimeMillis, parent, credential);
     }
 
@@ -657,7 +770,8 @@ private static AuthSession fromTokenResponse(
               response.issuedTokenType(),
               credential,
               parent.scope(),
-              parent.oauth2ServerUri());
+              parent.oauth2ServerUri(),
+              parent.optionalOAuthParams());
 
       Long expiresAtMillis = session.expiresAtMillis();
       if (null == expiresAtMillis && response.expiresInSeconds() != null) {
@@ -687,7 +801,8 @@ public static AuthSession fromTokenExchange(
               parent.token(),
               parent.tokenType(),
               parent.scope(),
-              parent.oauth2ServerUri());
+              parent.oauth2ServerUri(),
+              parent.optionalOAuthParams());
       return fromTokenResponse(client, executor, response, startTimeMillis, parent);
     }
   }
diff --git a/core/src/test/java/org/apache/iceberg/rest/TestRESTCatalog.java b/core/src/test/java/org/apache/iceberg/rest/TestRESTCatalog.java
index db67cfd4bb3f..18d832b3cd46 100644
--- a/core/src/test/java/org/apache/iceberg/rest/TestRESTCatalog.java
+++ b/core/src/test/java/org/apache/iceberg/rest/TestRESTCatalog.java
@@ -678,7 +678,8 @@ public void testClientBearerToken(String oauth2ServerUri) {
             "urn:ietf:params:oauth:token-type:saml2", "saml2-token",
             "urn:ietf:params:oauth:token-type:saml1", "saml1-token"),
         ImmutableMap.of("Authorization", "Bearer client-bearer-token"),
-        oauth2ServerUri);
+        oauth2ServerUri,
+        ImmutableMap.of());
   }
 
   @ParameterizedTest
@@ -694,7 +695,8 @@ public void testClientCredential(String oauth2ServerUri) {
             "urn:ietf:params:oauth:token-type:saml2", "saml2-token",
             "urn:ietf:params:oauth:token-type:saml1", "saml1-token"),
         ImmutableMap.of("Authorization", "Bearer client-credentials-token:sub=user"),
-        oauth2ServerUri);
+        oauth2ServerUri,
+        ImmutableMap.of());
   }
 
   @ParameterizedTest
@@ -710,7 +712,8 @@ public void testClientIDToken(String oauth2ServerUri) {
             "urn:ietf:params:oauth:token-type:saml1", "saml1-token"),
         ImmutableMap.of(
             "Authorization", "Bearer token-exchange-token:sub=id-token,act=bearer-token"),
-        oauth2ServerUri);
+        oauth2ServerUri,
+        ImmutableMap.of());
   }
 
   @ParameterizedTest
@@ -725,7 +728,25 @@ public void testClientAccessToken(String oauth2ServerUri) {
             "urn:ietf:params:oauth:token-type:saml1", "saml1-token"),
         ImmutableMap.of(
             "Authorization", "Bearer token-exchange-token:sub=access-token,act=bearer-token"),
-        oauth2ServerUri);
+        oauth2ServerUri,
+        ImmutableMap.of());
+  }
+
+  @ParameterizedTest
+  @ValueSource(strings = {"v1/oauth/tokens", "https://auth-server.com/token"})
+  public void testClientAccessTokenWithOptionalParams(String oauth2ServerUri) {
+    testClientAuth(
+        "bearer-token",
+        ImmutableMap.of(
+            "urn:ietf:params:oauth:token-type:access_token", "access-token",
+            "urn:ietf:params:oauth:token-type:jwt", "jwt-token",
+            "urn:ietf:params:oauth:token-type:saml2", "saml2-token",
+            "urn:ietf:params:oauth:token-type:saml1", "saml1-token"),
+        ImmutableMap.of(
+            "Authorization", "Bearer token-exchange-token:sub=access-token,act=bearer-token"),
+        oauth2ServerUri,
+        ImmutableMap.of(
+            "scope", "custom_scope", "audience", "test_audience", "resource", "test_resource"));
   }
 
   @ParameterizedTest
@@ -739,7 +760,8 @@ public void testClientJWTToken(String oauth2ServerUri) {
             "urn:ietf:params:oauth:token-type:saml1", "saml1-token"),
         ImmutableMap.of(
             "Authorization", "Bearer token-exchange-token:sub=jwt-token,act=bearer-token"),
-        oauth2ServerUri);
+        oauth2ServerUri,
+        ImmutableMap.of());
   }
 
   @ParameterizedTest
@@ -752,7 +774,8 @@ public void testClientSAML2Token(String oauth2ServerUri) {
             "urn:ietf:params:oauth:token-type:saml1", "saml1-token"),
         ImmutableMap.of(
             "Authorization", "Bearer token-exchange-token:sub=saml2-token,act=bearer-token"),
-        oauth2ServerUri);
+        oauth2ServerUri,
+        ImmutableMap.of());
   }
 
   @ParameterizedTest
@@ -763,14 +786,16 @@ public void testClientSAML1Token(String oauth2ServerUri) {
         ImmutableMap.of("urn:ietf:params:oauth:token-type:saml1", "saml1-token"),
         ImmutableMap.of(
             "Authorization", "Bearer token-exchange-token:sub=saml1-token,act=bearer-token"),
-        oauth2ServerUri);
+        oauth2ServerUri,
+        ImmutableMap.of());
   }
 
   private void testClientAuth(
       String catalogToken,
       Map<String, String> credentials,
       Map<String, String> expectedHeaders,
-      String oauth2ServerUri) {
+      String oauth2ServerUri,
+      Map<String, String> optionalOAuthParams) {
     Map<String, String> catalogHeaders = ImmutableMap.of("Authorization", "Bearer " + catalogToken);
 
     RESTCatalogAdapter adapter = Mockito.spy(new RESTCatalogAdapter(backendCatalog));
@@ -780,15 +805,16 @@ private void testClientAuth(
             UUID.randomUUID().toString(), "user", credentials, ImmutableMap.of());
 
     RESTCatalog catalog = new RESTCatalog(context, (config) -> adapter);
-    catalog.initialize(
-        "prod",
-        ImmutableMap.of(
-            CatalogProperties.URI,
-            "ignored",
-            "token",
-            catalogToken,
-            OAuth2Properties.OAUTH2_SERVER_URI,
-            oauth2ServerUri));
+
+    ImmutableMap.Builder<String, String> propertyBuilder = ImmutableMap.builder();
+    Map<String, String> initializationProperties =
+        propertyBuilder
+            .put(CatalogProperties.URI, "ignored")
+            .put("token", catalogToken)
+            .put(OAuth2Properties.OAUTH2_SERVER_URI, oauth2ServerUri)
+            .putAll(optionalOAuthParams)
+            .build();
+    catalog.initialize("prod", initializationProperties);
 
     Assertions.assertThat(catalog.tableExists(TableIdentifier.of("ns", "table"))).isFalse();
 
@@ -815,7 +841,6 @@ private void testClientAuth(
               eq(catalogHeaders),
               any());
     }
-
     Mockito.verify(adapter)
         .execute(
             eq(HTTPMethod.GET),
@@ -825,6 +850,21 @@ private void testClientAuth(
             eq(LoadTableResponse.class),
             eq(expectedHeaders),
             any());
+    if (!optionalOAuthParams.isEmpty()) {
+      Mockito.verify(adapter)
+          .execute(
+              eq(HTTPMethod.POST),
+              eq(oauth2ServerUri),
+              any(),
+              Mockito.argThat(
+                  body ->
+                      ((Map<String, String>) body)
+                          .keySet()
+                          .containsAll(optionalOAuthParams.keySet())),
+              eq(OAuthTokenResponse.class),
+              eq(catalogHeaders),
+              any());
+    }
   }
 
   @ParameterizedTest