diff --git a/src/Microsoft.OpenApi/Any/OpenApiPrimitive.cs b/src/Microsoft.OpenApi/Any/OpenApiPrimitive.cs
index bd6db956a..b8dcf097d 100644
--- a/src/Microsoft.OpenApi/Any/OpenApiPrimitive.cs
+++ b/src/Microsoft.OpenApi/Any/OpenApiPrimitive.cs
@@ -118,7 +118,7 @@ public void Write(IOpenApiWriter writer, OpenApiSpecVersion specVersion)
 
                 case PrimitiveType.Date:
                     var dateValue = (OpenApiDate)(IOpenApiPrimitive)this;
-                    writer.WriteValue(dateValue.Value.ToShortDateString());
+                    writer.WriteValue(dateValue.Value.ToString("o").Substring(0, 10));
                     break;
 
                 case PrimitiveType.DateTime:
diff --git a/test/Microsoft.OpenApi.Tests/Models/OpenApiExampleTests.SerializeReferencedExampleAsV3JsonWithoutReferenceWorks_produceTerseOutput=False.verified.txt b/test/Microsoft.OpenApi.Tests/Models/OpenApiExampleTests.SerializeReferencedExampleAsV3JsonWithoutReferenceWorks_produceTerseOutput=False.verified.txt
index 868b45156..bbe6f7e93 100644
--- a/test/Microsoft.OpenApi.Tests/Models/OpenApiExampleTests.SerializeReferencedExampleAsV3JsonWithoutReferenceWorks_produceTerseOutput=False.verified.txt
+++ b/test/Microsoft.OpenApi.Tests/Models/OpenApiExampleTests.SerializeReferencedExampleAsV3JsonWithoutReferenceWorks_produceTerseOutput=False.verified.txt
@@ -22,6 +22,6 @@
         ]
       }
     ],
-    "aDate": "12/12/2022"
+    "aDate": "2022-12-12"
   }
 }
\ No newline at end of file
diff --git a/test/Microsoft.OpenApi.Tests/Models/OpenApiExampleTests.SerializeReferencedExampleAsV3JsonWithoutReferenceWorks_produceTerseOutput=True.verified.txt b/test/Microsoft.OpenApi.Tests/Models/OpenApiExampleTests.SerializeReferencedExampleAsV3JsonWithoutReferenceWorks_produceTerseOutput=True.verified.txt
index 7ab9ad1d6..e84267af4 100644
--- a/test/Microsoft.OpenApi.Tests/Models/OpenApiExampleTests.SerializeReferencedExampleAsV3JsonWithoutReferenceWorks_produceTerseOutput=True.verified.txt
+++ b/test/Microsoft.OpenApi.Tests/Models/OpenApiExampleTests.SerializeReferencedExampleAsV3JsonWithoutReferenceWorks_produceTerseOutput=True.verified.txt
@@ -1 +1 @@
-{"value":{"versions":[{"status":"Status1","id":"v1","links":[{"href":"http://example.com/1","rel":"sampleRel1"}]},{"status":"Status2","id":"v2","links":[{"href":"http://example.com/2","rel":"sampleRel2"}]}],"aDate":"12/12/2022"}}
\ No newline at end of file
+{"value":{"versions":[{"status":"Status1","id":"v1","links":[{"href":"http://example.com/1","rel":"sampleRel1"}]},{"status":"Status2","id":"v2","links":[{"href":"http://example.com/2","rel":"sampleRel2"}]}],"aDate":"2022-12-12"}}
\ No newline at end of file