diff --git a/compiler/crates/common/src/feature_flags.rs b/compiler/crates/common/src/feature_flags.rs
index 9cc2d8fc4b6e1..7d7e047b8519a 100644
--- a/compiler/crates/common/src/feature_flags.rs
+++ b/compiler/crates/common/src/feature_flags.rs
@@ -179,6 +179,14 @@ pub struct FeatureFlags {
     /// across a number of diffs.
     #[serde(default)]
     pub legacy_include_path_in_required_reader_nodes: FeatureFlag,
+
+    /// Produce native GraphQL fragment spreads when spreading a fragment with
+    /// @relay(mask: false) into a query, instead of inlining the contents of
+    /// that fragment for each use. This significantly reduces the uncompressed
+    /// size of query text when several mask:false fragment spreads are present,
+    /// but has no impact on masking behavior.
+    #[serde(default)]
+    pub use_native_fragment_spreads_for_unmasked_fragments: bool,
 }
 
 #[derive(Debug, serde::Deserialize, Clone, Serialize, Default, JsonSchema)]
diff --git a/compiler/crates/relay-compiler/relay-compiler-config-schema.json b/compiler/crates/relay-compiler/relay-compiler-config-schema.json
index 3973a80e78c59..7a17b5f727a3f 100644
--- a/compiler/crates/relay-compiler/relay-compiler-config-schema.json
+++ b/compiler/crates/relay-compiler/relay-compiler-config-schema.json
@@ -841,6 +841,11 @@
             }
           ]
         },
+        "use_native_fragment_spreads_for_unmasked_fragments": {
+          "description": "Produce native GraphQL fragment spreads when spreading a fragment with @relay(mask: false) into a query, instead of inlining the contents of that fragment for each use. This significantly reduces the uncompressed size of query text when several mask:false fragment spreads are present, but has no impact on masking behavior.",
+          "default": false,
+          "type": "boolean"
+        },
         "use_reader_module_imports": {
           "description": "Generate the `moduleImports` field in the Reader AST.",
           "default": {
@@ -1082,6 +1087,7 @@
             "text_artifacts": {
               "kind": "disabled"
             },
+            "use_native_fragment_spreads_for_unmasked_fragments": false,
             "use_reader_module_imports": {
               "kind": "disabled"
             }
diff --git a/compiler/crates/relay-compiler/tests/compile_relay_artifacts/fixtures/unmasked-fragment-spreads-in-query-inline-disabled.expected b/compiler/crates/relay-compiler/tests/compile_relay_artifacts/fixtures/unmasked-fragment-spreads-in-query-inline-disabled.expected
new file mode 100644
index 0000000000000..ec10c32812ec6
--- /dev/null
+++ b/compiler/crates/relay-compiler/tests/compile_relay_artifacts/fixtures/unmasked-fragment-spreads-in-query-inline-disabled.expected
@@ -0,0 +1,370 @@
+==================================== INPUT ====================================
+query unmaskedFragmentSpreadsInQueryInlineDisabled_TestQuery($isRelative: Boolean) {
+  me {
+    ...unmaskedFragmentSpreadsInQueryInlineDisabled_UserUtil_user @relay(mask: false)
+    nearest_neighbor {
+      ...unmaskedFragmentSpreadsInQueryInlineDisabled_UserUtil_user @relay(mask: false)
+    }
+  }
+}
+
+fragment unmaskedFragmentSpreadsInQueryInlineDisabled_UserUtil_user on User {
+  url(relative: $isRelative)
+  canViewerLike
+  doesViewerLike
+  lastName
+  name
+}
+
+%project_config%
+{
+  "language": "flow",
+  "jsModuleFormat": "haste",
+  "featureFlags": {
+    "use_native_fragment_spreads_for_unmasked_fragments": true
+  }
+}
+==================================== OUTPUT ===================================
+{
+  "fragment": {
+    "argumentDefinitions": [
+      {
+        "defaultValue": null,
+        "kind": "LocalArgument",
+        "name": "isRelative"
+      }
+    ],
+    "kind": "Fragment",
+    "metadata": null,
+    "name": "unmaskedFragmentSpreadsInQueryInlineDisabled_TestQuery",
+    "selections": [
+      {
+        "alias": null,
+        "args": null,
+        "concreteType": "User",
+        "kind": "LinkedField",
+        "name": "me",
+        "plural": false,
+        "selections": [
+          {
+            "alias": null,
+            "args": [
+              {
+                "kind": "Variable",
+                "name": "relative",
+                "variableName": "isRelative"
+              }
+            ],
+            "kind": "ScalarField",
+            "name": "url",
+            "storageKey": null
+          },
+          {
+            "alias": null,
+            "args": null,
+            "kind": "ScalarField",
+            "name": "canViewerLike",
+            "storageKey": null
+          },
+          {
+            "alias": null,
+            "args": null,
+            "kind": "ScalarField",
+            "name": "doesViewerLike",
+            "storageKey": null
+          },
+          {
+            "alias": null,
+            "args": null,
+            "kind": "ScalarField",
+            "name": "lastName",
+            "storageKey": null
+          },
+          {
+            "alias": null,
+            "args": null,
+            "kind": "ScalarField",
+            "name": "name",
+            "storageKey": null
+          },
+          {
+            "alias": null,
+            "args": null,
+            "concreteType": "User",
+            "kind": "LinkedField",
+            "name": "nearest_neighbor",
+            "plural": false,
+            "selections": [
+              {
+                "alias": null,
+                "args": [
+                  {
+                    "kind": "Variable",
+                    "name": "relative",
+                    "variableName": "isRelative"
+                  }
+                ],
+                "kind": "ScalarField",
+                "name": "url",
+                "storageKey": null
+              },
+              {
+                "alias": null,
+                "args": null,
+                "kind": "ScalarField",
+                "name": "canViewerLike",
+                "storageKey": null
+              },
+              {
+                "alias": null,
+                "args": null,
+                "kind": "ScalarField",
+                "name": "doesViewerLike",
+                "storageKey": null
+              },
+              {
+                "alias": null,
+                "args": null,
+                "kind": "ScalarField",
+                "name": "lastName",
+                "storageKey": null
+              },
+              {
+                "alias": null,
+                "args": null,
+                "kind": "ScalarField",
+                "name": "name",
+                "storageKey": null
+              }
+            ],
+            "storageKey": null
+          }
+        ],
+        "storageKey": null
+      }
+    ],
+    "type": "Query",
+    "abstractKey": null
+  },
+  "kind": "Request",
+  "operation": {
+    "argumentDefinitions": [
+      {
+        "defaultValue": null,
+        "kind": "LocalArgument",
+        "name": "isRelative"
+      }
+    ],
+    "kind": "Operation",
+    "name": "unmaskedFragmentSpreadsInQueryInlineDisabled_TestQuery",
+    "selections": [
+      {
+        "alias": null,
+        "args": null,
+        "concreteType": "User",
+        "kind": "LinkedField",
+        "name": "me",
+        "plural": false,
+        "selections": [
+          {
+            "alias": null,
+            "args": [
+              {
+                "kind": "Variable",
+                "name": "relative",
+                "variableName": "isRelative"
+              }
+            ],
+            "kind": "ScalarField",
+            "name": "url",
+            "storageKey": null
+          },
+          {
+            "alias": null,
+            "args": null,
+            "kind": "ScalarField",
+            "name": "canViewerLike",
+            "storageKey": null
+          },
+          {
+            "alias": null,
+            "args": null,
+            "kind": "ScalarField",
+            "name": "doesViewerLike",
+            "storageKey": null
+          },
+          {
+            "alias": null,
+            "args": null,
+            "kind": "ScalarField",
+            "name": "lastName",
+            "storageKey": null
+          },
+          {
+            "alias": null,
+            "args": null,
+            "kind": "ScalarField",
+            "name": "name",
+            "storageKey": null
+          },
+          {
+            "alias": null,
+            "args": null,
+            "concreteType": "User",
+            "kind": "LinkedField",
+            "name": "nearest_neighbor",
+            "plural": false,
+            "selections": [
+              {
+                "alias": null,
+                "args": [
+                  {
+                    "kind": "Variable",
+                    "name": "relative",
+                    "variableName": "isRelative"
+                  }
+                ],
+                "kind": "ScalarField",
+                "name": "url",
+                "storageKey": null
+              },
+              {
+                "alias": null,
+                "args": null,
+                "kind": "ScalarField",
+                "name": "canViewerLike",
+                "storageKey": null
+              },
+              {
+                "alias": null,
+                "args": null,
+                "kind": "ScalarField",
+                "name": "doesViewerLike",
+                "storageKey": null
+              },
+              {
+                "alias": null,
+                "args": null,
+                "kind": "ScalarField",
+                "name": "lastName",
+                "storageKey": null
+              },
+              {
+                "alias": null,
+                "args": null,
+                "kind": "ScalarField",
+                "name": "name",
+                "storageKey": null
+              },
+              {
+                "alias": null,
+                "args": null,
+                "kind": "ScalarField",
+                "name": "id",
+                "storageKey": null
+              }
+            ],
+            "storageKey": null
+          },
+          {
+            "alias": null,
+            "args": null,
+            "kind": "ScalarField",
+            "name": "id",
+            "storageKey": null
+          }
+        ],
+        "storageKey": null
+      }
+    ]
+  },
+  "params": {
+    "cacheID": "3de23a25a89b722aee3f7748aa98647b",
+    "id": null,
+    "metadata": {},
+    "name": "unmaskedFragmentSpreadsInQueryInlineDisabled_TestQuery",
+    "operationKind": "query",
+    "text": null
+  }
+}
+
+QUERY:
+
+query unmaskedFragmentSpreadsInQueryInlineDisabled_TestQuery(
+  $isRelative: Boolean
+) {
+  me {
+    ...unmaskedFragmentSpreadsInQueryInlineDisabled_UserUtil_user
+    nearest_neighbor {
+      ...unmaskedFragmentSpreadsInQueryInlineDisabled_UserUtil_user
+      id
+    }
+    id
+  }
+}
+
+fragment unmaskedFragmentSpreadsInQueryInlineDisabled_UserUtil_user on User {
+  url(relative: $isRelative)
+  canViewerLike
+  doesViewerLike
+  lastName
+  name
+}
+
+
+{
+  "argumentDefinitions": [
+    {
+      "kind": "RootArgument",
+      "name": "isRelative"
+    }
+  ],
+  "kind": "Fragment",
+  "metadata": null,
+  "name": "unmaskedFragmentSpreadsInQueryInlineDisabled_UserUtil_user",
+  "selections": [
+    {
+      "alias": null,
+      "args": [
+        {
+          "kind": "Variable",
+          "name": "relative",
+          "variableName": "isRelative"
+        }
+      ],
+      "kind": "ScalarField",
+      "name": "url",
+      "storageKey": null
+    },
+    {
+      "alias": null,
+      "args": null,
+      "kind": "ScalarField",
+      "name": "canViewerLike",
+      "storageKey": null
+    },
+    {
+      "alias": null,
+      "args": null,
+      "kind": "ScalarField",
+      "name": "doesViewerLike",
+      "storageKey": null
+    },
+    {
+      "alias": null,
+      "args": null,
+      "kind": "ScalarField",
+      "name": "lastName",
+      "storageKey": null
+    },
+    {
+      "alias": null,
+      "args": null,
+      "kind": "ScalarField",
+      "name": "name",
+      "storageKey": null
+    }
+  ],
+  "type": "User",
+  "abstractKey": null
+}
diff --git a/compiler/crates/relay-compiler/tests/compile_relay_artifacts/fixtures/unmasked-fragment-spreads-in-query-inline-disabled.graphql b/compiler/crates/relay-compiler/tests/compile_relay_artifacts/fixtures/unmasked-fragment-spreads-in-query-inline-disabled.graphql
new file mode 100644
index 0000000000000..b54d742b373c3
--- /dev/null
+++ b/compiler/crates/relay-compiler/tests/compile_relay_artifacts/fixtures/unmasked-fragment-spreads-in-query-inline-disabled.graphql
@@ -0,0 +1,25 @@
+query unmaskedFragmentSpreadsInQueryInlineDisabled_TestQuery($isRelative: Boolean) {
+  me {
+    ...unmaskedFragmentSpreadsInQueryInlineDisabled_UserUtil_user @relay(mask: false)
+    nearest_neighbor {
+      ...unmaskedFragmentSpreadsInQueryInlineDisabled_UserUtil_user @relay(mask: false)
+    }
+  }
+}
+
+fragment unmaskedFragmentSpreadsInQueryInlineDisabled_UserUtil_user on User {
+  url(relative: $isRelative)
+  canViewerLike
+  doesViewerLike
+  lastName
+  name
+}
+
+%project_config%
+{
+  "language": "flow",
+  "jsModuleFormat": "haste",
+  "featureFlags": {
+    "use_native_fragment_spreads_for_unmasked_fragments": true
+  }
+}
diff --git a/compiler/crates/relay-compiler/tests/compile_relay_artifacts_test.rs b/compiler/crates/relay-compiler/tests/compile_relay_artifacts_test.rs
index cda842e6e73d5..8ac840e912a71 100644
--- a/compiler/crates/relay-compiler/tests/compile_relay_artifacts_test.rs
+++ b/compiler/crates/relay-compiler/tests/compile_relay_artifacts_test.rs
@@ -4,7 +4,7 @@
  * This source code is licensed under the MIT license found in the
  * LICENSE file in the root directory of this source tree.
  *
- * @generated SignedSource<<67aa79681f4c3c1406944dd059174dc7>>
+ * @generated SignedSource<<642d3b0a3533bbca281898c58d5d62a4>>
  */
 
 mod compile_relay_artifacts;
@@ -2028,6 +2028,13 @@ async fn unmasked_fragment_spreads_global_arguments() {
     test_fixture(transform_fixture, file!(), "unmasked-fragment-spreads-global-arguments.graphql", "compile_relay_artifacts/fixtures/unmasked-fragment-spreads-global-arguments.expected", input, expected).await;
 }
 
+#[tokio::test]
+async fn unmasked_fragment_spreads_in_query_inline_disabled() {
+    let input = include_str!("compile_relay_artifacts/fixtures/unmasked-fragment-spreads-in-query-inline-disabled.graphql");
+    let expected = include_str!("compile_relay_artifacts/fixtures/unmasked-fragment-spreads-in-query-inline-disabled.expected");
+    test_fixture(transform_fixture, file!(), "unmasked-fragment-spreads-in-query-inline-disabled.graphql", "compile_relay_artifacts/fixtures/unmasked-fragment-spreads-in-query-inline-disabled.expected", input, expected).await;
+}
+
 #[tokio::test]
 async fn unmasked_fragment_spreads_local_arguments_invalid() {
     let input = include_str!("compile_relay_artifacts/fixtures/unmasked-fragment-spreads-local-arguments.invalid.graphql");
diff --git a/compiler/crates/relay-transforms/src/apply_transforms.rs b/compiler/crates/relay-transforms/src/apply_transforms.rs
index b611764033302..f9cb2a88caac8 100644
--- a/compiler/crates/relay-transforms/src/apply_transforms.rs
+++ b/compiler/crates/relay-transforms/src/apply_transforms.rs
@@ -186,7 +186,13 @@ fn apply_common_transforms(
             false,
         )
     });
-    program = log_event.time("mask", || mask(&program));
+
+    if !project_config
+        .feature_flags
+        .use_native_fragment_spreads_for_unmasked_fragments
+    {
+        program = log_event.time("mask", || mask(&program));
+    }
     program = log_event.time("transform_defer_stream", || {
         transform_defer_stream(
             &program,
@@ -277,6 +283,8 @@ fn apply_reader_transforms(
         None,
     )?;
 
+    program = log_event.time("mask", || mask(&program));
+
     program = log_event.time("required_directive", || required_directive(&program))?;
 
     program = log_event.time("catch_directive", || catch_directive(&program))?;
@@ -574,6 +582,13 @@ fn apply_operation_text_transforms(
         )
     })?;
 
+    if !project_config
+        .feature_flags
+        .use_native_fragment_spreads_for_unmasked_fragments
+    {
+        program = log_event.time("mask", || mask(&program));
+    }
+
     log_event.time("validate_global_variables", || {
         validate_global_variables(&program)
     })?;