diff --git a/docs/source-1.0/spec/core/protocol-traits.rst b/docs/source-1.0/spec/core/protocol-traits.rst
index fce1a281d9c..449e48a8d0a 100644
--- a/docs/source-1.0/spec/core/protocol-traits.rst
+++ b/docs/source-1.0/spec/core/protocol-traits.rst
@@ -310,10 +310,7 @@ Smithy defines the following built-in timestamp formats:
     * - http-date
       - An HTTP date as defined by the ``IMF-fixdate`` production in
         :rfc:`7231#section-7.1.1.1` (for example,
-        ``Tue, 29 Apr 2014 18:30:38 GMT``). Note that in addition to the
-        ``IMF-fixdate`` format specified in the RFC, implementations MUST
-        also support optional fractional seconds (for example,
-        ``Sun, 02 Jan 2000 20:34:56.000 GMT``).
+        ``Tue, 29 Apr 2014 18:30:38 GMT``).
     * - epoch-seconds
       - Also known as Unix time, the number of seconds that have elapsed since
         00:00:00 Coordinated Universal Time (UTC), Thursday, 1 January 1970,
diff --git a/docs/source-2.0/spec/protocol-traits.rst b/docs/source-2.0/spec/protocol-traits.rst
index 56da9ff2182..ebe284fa7d9 100644
--- a/docs/source-2.0/spec/protocol-traits.rst
+++ b/docs/source-2.0/spec/protocol-traits.rst
@@ -226,10 +226,7 @@ Smithy defines the following built-in timestamp formats:
     * - http-date
       - An HTTP date as defined by the ``IMF-fixdate`` production in
         :rfc:`7231#section-7.1.1.1` (for example,
-        ``Tue, 29 Apr 2014 18:30:38 GMT``). Note that in addition to the
-        ``IMF-fixdate`` format specified in the RFC, implementations MUST
-        also support optional fractional seconds (for example,
-        ``Sun, 02 Jan 2000 20:34:56.000 GMT``).
+        ``Tue, 29 Apr 2014 18:30:38 GMT``).
     * - epoch-seconds
       - Also known as Unix time, the number of seconds that have elapsed since
         00:00:00 Coordinated Universal Time (UTC), Thursday, 1 January 1970,
diff --git a/smithy-aws-protocol-tests/model/awsJson1_1/fractional-seconds.smithy b/smithy-aws-protocol-tests/model/awsJson1_1/fractional-seconds.smithy
index 046bf9d8943..025e91ecec6 100644
--- a/smithy-aws-protocol-tests/model/awsJson1_1/fractional-seconds.smithy
+++ b/smithy-aws-protocol-tests/model/awsJson1_1/fractional-seconds.smithy
@@ -4,11 +4,9 @@ namespace aws.protocoltests.json
 
 use aws.protocols#awsJson1_1
 use aws.protocoltests.shared#DateTime
-use aws.protocoltests.shared#HttpDate
 use smithy.test#httpResponseTests
 
-// These tests are for verifying the client can correctly parse
-// the `DateTime` and `HttpDate` timestamps with fractional seconds
+// These tests verify that clients can parse `DateTime` timestamps with fractional seconds.
 @tags(["client-only"])
 operation FractionalSeconds {
     output: FractionalSecondsOutput
@@ -33,29 +31,9 @@ apply FractionalSeconds @httpResponseTests([
             "Content-Type": "application/x-amz-json-1.1"
         },
         appliesTo: "client"
-    },
-    {
-        id: "AwsJson11HttpDateWithFractionalSeconds",
-        documentation: """
-        Ensures that clients can correctly parse http-date timestamps with fractional seconds""",
-        protocol: awsJson1_1,
-        code: 200,
-        body:
-        """
-              {
-                  "httpdate": "Sun, 02 Jan 2000 20:34:56.456 GMT"
-              }
-        """,
-        params: { httpdate: 946845296.456 }
-        bodyMediaType: "application/json",
-        headers: {
-            "Content-Type": "application/x-amz-json-1.1"
-        },
-        appliesTo: "client"
     }
 ])
 
 structure FractionalSecondsOutput {
     datetime: DateTime
-    httpdate: HttpDate
 }
diff --git a/smithy-aws-protocol-tests/model/awsQuery/fractional-seconds.smithy b/smithy-aws-protocol-tests/model/awsQuery/fractional-seconds.smithy
index 99d4f2411f3..10cfcda5db1 100644
--- a/smithy-aws-protocol-tests/model/awsQuery/fractional-seconds.smithy
+++ b/smithy-aws-protocol-tests/model/awsQuery/fractional-seconds.smithy
@@ -4,11 +4,9 @@ namespace aws.protocoltests.query
 
 use aws.protocols#awsQuery
 use aws.protocoltests.shared#DateTime
-use aws.protocoltests.shared#HttpDate
 use smithy.test#httpResponseTests
 
-// These tests are for verifying the client can correctly parse
-// the `DateTime` and `HttpDate` timestamps with fractional seconds
+// These tests verify that clients can parse `DateTime` timestamps with fractional seconds.
 @tags(["client-only"])
 operation FractionalSeconds {
     output: FractionalSecondsOutput
@@ -35,29 +33,8 @@ apply FractionalSeconds @httpResponseTests([
         },
         appliesTo: "client"
     }
-    {
-        id: "AwsQueryHttpDateWithFractionalSeconds",
-        documentation: """
-        Ensures that clients can correctly parse http-date timestamps with fractional seconds""",
-        protocol: awsQuery,
-        code: 200,
-        body: """
-              <FractionalSecondsResponse xmlns="https://example.com/">
-                  <FractionalSecondsResult>
-                      <httpdate>Sun, 02 Jan 2000 20:34:56.456 GMT</httpdate>
-                  </FractionalSecondsResult>
-              </FractionalSecondsResponse>
-              """,
-        params: { httpdate: 946845296.456 }
-        bodyMediaType: "application/xml",
-        headers: {
-            "Content-Type": "text/xml"
-        },
-        appliesTo: "client"
-    }
 ])
 
 structure FractionalSecondsOutput {
     datetime: DateTime
-    httpdate: HttpDate
 }
diff --git a/smithy-aws-protocol-tests/model/ec2Query/fractional-seconds.smithy b/smithy-aws-protocol-tests/model/ec2Query/fractional-seconds.smithy
index e566255b305..bbda602b730 100644
--- a/smithy-aws-protocol-tests/model/ec2Query/fractional-seconds.smithy
+++ b/smithy-aws-protocol-tests/model/ec2Query/fractional-seconds.smithy
@@ -4,11 +4,9 @@ namespace aws.protocoltests.ec2
 
 use aws.protocols#ec2Query
 use aws.protocoltests.shared#DateTime
-use aws.protocoltests.shared#HttpDate
 use smithy.test#httpResponseTests
 
-// These tests are for verifying the client can correctly parse
-// the `DateTime` and `HttpDate` timestamps with fractional seconds
+// These tests verify that clients can parse `DateTime` timestamps with fractional seconds.
 @tags(["client-only"])
 operation FractionalSeconds {
     output: FractionalSecondsOutput
@@ -32,28 +30,9 @@ apply FractionalSeconds @httpResponseTests([
             "Content-Type": "text/xml;charset=UTF-8"
         },
         params: { datetime: 946845296.123 }
-    },
-    {
-        id: "Ec2QueryHttpDateWithFractionalSeconds",
-        documentation: """
-        Ensures that clients can correctly parse http-date timestamps with fractional seconds""",
-        protocol: ec2Query,
-        code: 200,
-        body: """
-              <FractionalSecondsResponse xmlns="https://example.com/">
-                  <httpdate>Sun, 02 Jan 2000 20:34:56.456 GMT</httpdate>
-                  <RequestId>requestid</RequestId>
-              </FractionalSecondsResponse>
-              """,
-        bodyMediaType: "application/xml",
-        headers: {
-            "Content-Type": "text/xml;charset=UTF-8"
-        },
-        params: { httpdate: 946845296.456 }
     }
 ])
 
 structure FractionalSecondsOutput {
     datetime: DateTime
-    httpdate: HttpDate
 }
diff --git a/smithy-aws-protocol-tests/model/restJson1/fractional-seconds.smithy b/smithy-aws-protocol-tests/model/restJson1/fractional-seconds.smithy
index f9c914fd725..cb0d624a653 100644
--- a/smithy-aws-protocol-tests/model/restJson1/fractional-seconds.smithy
+++ b/smithy-aws-protocol-tests/model/restJson1/fractional-seconds.smithy
@@ -4,11 +4,9 @@ namespace aws.protocoltests.restjson
 
 use aws.protocols#restJson1
 use aws.protocoltests.shared#DateTime
-use aws.protocoltests.shared#HttpDate
 use smithy.test#httpResponseTests
 
-// These tests are for verifying the client can correctly parse
-// the `DateTime` and `HttpDate` timestamps with fractional seconds
+// These tests verify that clients can parse `DateTime` timestamps with fractional seconds.
 @tags(["client-only"])
 @http(uri: "/FractionalSeconds", method: "POST")
 operation FractionalSeconds {
@@ -31,26 +29,9 @@ apply FractionalSeconds @httpResponseTests([
         params: { datetime: 946845296.123 }
         bodyMediaType: "application/json",
         appliesTo: "client"
-    },
-    {
-        id: "RestJsonHttpDateWithFractionalSeconds",
-        documentation: """
-        Ensures that clients can correctly parse http-date timestamps with fractional seconds""",
-        protocol: restJson1,
-        code: 200,
-        body:
-        """
-              {
-                  "httpdate": "Sun, 02 Jan 2000 20:34:56.456 GMT"
-              }
-        """,
-        params: { httpdate: 946845296.456 }
-        bodyMediaType: "application/json",
-        appliesTo: "client"
     }
 ])
 
 structure FractionalSecondsOutput {
     datetime: DateTime
-    httpdate: HttpDate
 }
diff --git a/smithy-aws-protocol-tests/model/restJson1/malformedRequests/malformed-timestamp-body.smithy b/smithy-aws-protocol-tests/model/restJson1/malformedRequests/malformed-timestamp-body.smithy
index a9dafd0faaa..ecdd1419106 100644
--- a/smithy-aws-protocol-tests/model/restJson1/malformedRequests/malformed-timestamp-body.smithy
+++ b/smithy-aws-protocol-tests/model/restJson1/malformedRequests/malformed-timestamp-body.smithy
@@ -126,8 +126,7 @@ apply MalformedTimestampBodyDefault @httpMalformedRequestTests([
             }
         },
         testParameters: {
-            "value" : ["Tue, 29 Apr 2014 18:30:38 GMT",
-                       "Sun, 02 Jan 2000 20:34:56.000 GMT"]
+            "value" : ["Tue, 29 Apr 2014 18:30:38 GMT"]
         },
         tags : ["timestamp"]
     },
@@ -156,8 +155,7 @@ apply MalformedTimestampBodyDateTime @httpMalformedRequestTests([
             }
         },
         testParameters: {
-            "value" : ["Tue, 29 Apr 2014 18:30:38 GMT",
-                       "Sun, 02 Jan 2000 20:34:56.000 GMT"]
+            "value" : ["Tue, 29 Apr 2014 18:30:38 GMT"]
         },
         tags : ["timestamp"]
     },
diff --git a/smithy-aws-protocol-tests/model/restJson1/malformedRequests/malformed-timestamp-header.smithy b/smithy-aws-protocol-tests/model/restJson1/malformedRequests/malformed-timestamp-header.smithy
index d56b78bf580..fa33a1d397a 100644
--- a/smithy-aws-protocol-tests/model/restJson1/malformedRequests/malformed-timestamp-header.smithy
+++ b/smithy-aws-protocol-tests/model/restJson1/malformedRequests/malformed-timestamp-header.smithy
@@ -97,8 +97,7 @@ apply MalformedTimestampHeaderDateTime @httpMalformedRequestTests([
             }
         },
         testParameters: {
-            "value" : ["Tue, 29 Apr 2014 18:30:38 GMT",
-                       "Sun, 02 Jan 2000 20:34:56.000 GMT"]
+            "value" : ["Tue, 29 Apr 2014 18:30:38 GMT"]
         },
         tags : ["timestamp"]
     },
@@ -213,8 +212,7 @@ apply MalformedTimestampHeaderEpoch @httpMalformedRequestTests([
             }
         },
         testParameters: {
-            "value" : ["Tue, 29 Apr 2014 18:30:38 GMT",
-                       "Sun, 02 Jan 2000 20:34:56.000 GMT"]
+            "value" : ["Tue, 29 Apr 2014 18:30:38 GMT"]
         },
         tags : ["timestamp"]
     },
diff --git a/smithy-aws-protocol-tests/model/restJson1/validation/malformed-uniqueItems.smithy b/smithy-aws-protocol-tests/model/restJson1/validation/malformed-uniqueItems.smithy
index 252c6825f52..58b5e66b6ab 100644
--- a/smithy-aws-protocol-tests/model/restJson1/validation/malformed-uniqueItems.smithy
+++ b/smithy-aws-protocol-tests/model/restJson1/validation/malformed-uniqueItems.smithy
@@ -333,7 +333,7 @@ apply MalformedUniqueItems @httpMalformedRequestTests([
             }
         },
         testParameters: {
-            value: ["[\"Tue, 29 Apr 2014 18:30:38 GMT\", \"Tue, 29 Apr 2014 18:30:38 GMT\"]", "[\"Sun, 02 Jan 2000 20:34:56.000 GMT\", \"Sun, 02 Jan 2000 20:34:56.000 GMT\"]"]
+            value: ["[\"Tue, 29 Apr 2014 18:30:38 GMT\", \"Tue, 29 Apr 2014 18:30:38 GMT\"]"]
         }
     },
     {
diff --git a/smithy-aws-protocol-tests/model/restXml/fractional-seconds.smithy b/smithy-aws-protocol-tests/model/restXml/fractional-seconds.smithy
index 8f8ee856c7e..dc5cb78a38d 100644
--- a/smithy-aws-protocol-tests/model/restXml/fractional-seconds.smithy
+++ b/smithy-aws-protocol-tests/model/restXml/fractional-seconds.smithy
@@ -4,11 +4,9 @@ namespace aws.protocoltests.restxml
 
 use aws.protocols#restXml
 use aws.protocoltests.shared#DateTime
-use aws.protocoltests.shared#HttpDate
 use smithy.test#httpResponseTests
 
-// These tests are for verifying the client can correctly parse
-// the `DateTime` and `HttpDate` timestamps with fractional seconds
+// These tests verify that clients can parse `DateTime` timestamps with fractional seconds.
 @tags(["client-only"])
 @http(uri: "/FractionalSeconds", method: "POST")
 operation FractionalSeconds {
@@ -32,27 +30,9 @@ apply FractionalSeconds @httpResponseTests([
             "Content-Type": "application/xml"
         },
         params: { datetime: 946845296.123 }
-    },
-    {
-        id: "RestXmlHttpDateWithFractionalSeconds",
-        documentation: """
-        Ensures that clients can correctly parse http-date timestamps with fractional seconds""",
-        protocol: restXml,
-        code: 200,
-        body: """
-            <FractionalSecondsOutput>
-                <httpdate>Sun, 02 Jan 2000 20:34:56.456 GMT</httpdate>
-            </FractionalSecondsOutput>
-            """,
-        bodyMediaType: "application/xml",
-        headers: {
-            "Content-Type": "application/xml"
-        },
-        params: { httpdate: 946845296.456 }
     }
 ])
 
 structure FractionalSecondsOutput {
     datetime: DateTime
-    httpdate: HttpDate
 }