diff --git a/global.json b/global.json
index 459fe3e6e..d72c3f669 100644
--- a/global.json
+++ b/global.json
@@ -1,5 +1,5 @@
 {
   "sdk": {
-    "version": "8.0.418"
+    "version": "8.0.419"
   }
 }
\ No newline at end of file
diff --git a/src/Microsoft.OpenApi/Models/OpenApiSchema.cs b/src/Microsoft.OpenApi/Models/OpenApiSchema.cs
index 85f899bf5..fd802f13a 100644
--- a/src/Microsoft.OpenApi/Models/OpenApiSchema.cs
+++ b/src/Microsoft.OpenApi/Models/OpenApiSchema.cs
@@ -542,19 +542,24 @@ private void SerializeInternal(IOpenApiWriter writer, OpenApiSpecVersion version
             // For versions < 3.1, write unevaluatedProperties as an extension
             if (version < OpenApiSpecVersion.OpenApi3_1)
             {
-                // Write UnevaluatedPropertiesSchema as extension if present
-                if (UnevaluatedPropertiesSchema is not null)
+                // Only emit unevaluatedProperties when the type could include objects.
+                // Skip when type is explicitly set to a non-object type (array, string, number, integer, boolean, null).
+                if (!Type.HasValue || (Type.Value & JsonSchemaType.Object) != 0)
                 {
-                    writer.WriteOptionalObject(
-                        OpenApiConstants.UnevaluatedPropertiesExtension,
-                        UnevaluatedPropertiesSchema,
-                        callback);
-                }
-                // Write boolean false as extension if explicitly set to false
-                else if (!UnevaluatedProperties)
-                {
-                    writer.WritePropertyName(OpenApiConstants.UnevaluatedPropertiesExtension);
-                    writer.WriteValue(false);
+                    // Write UnevaluatedPropertiesSchema as extension if present
+                    if (UnevaluatedPropertiesSchema is not null)
+                    {
+                        writer.WriteOptionalObject(
+                            OpenApiConstants.UnevaluatedPropertiesExtension,
+                            UnevaluatedPropertiesSchema,
+                            callback);
+                    }
+                    // Write boolean false as extension if explicitly set to false
+                    else if (!UnevaluatedProperties)
+                    {
+                        writer.WritePropertyName(OpenApiConstants.UnevaluatedPropertiesExtension);
+                        writer.WriteValue(false);
+                    }
                 }
 
                 // Write patternProperties as an extension
@@ -594,19 +599,23 @@ internal void WriteJsonSchemaKeywords(IOpenApiWriter writer)
             writer.WriteProperty(OpenApiConstants.DynamicRef, DynamicRef);
             writer.WriteProperty(OpenApiConstants.DynamicAnchor, DynamicAnchor);
             
-            // UnevaluatedProperties: similar to AdditionalProperties, serialize as schema if present, else as boolean
-            if (UnevaluatedPropertiesSchema is not null)
-            {
-                writer.WriteOptionalObject(
-                    OpenApiConstants.UnevaluatedProperties,
-                    UnevaluatedPropertiesSchema,
-                    (w, s) => s.SerializeAsV31(w));
-            }
-            else if (!UnevaluatedProperties)
+            // UnevaluatedProperties: similar to AdditionalProperties, serialize as schema if present, else as boolean.
+            // Only emit when the type could include objects.
+            // Skip when type is explicitly set to a non-object type (array, string, number, integer, boolean, null).
+            if (!Type.HasValue || (Type.Value & JsonSchemaType.Object) != 0)
             {
-                writer.WriteProperty(OpenApiConstants.UnevaluatedProperties, UnevaluatedProperties);
+                if (UnevaluatedPropertiesSchema is not null)
+                {
+                    writer.WriteOptionalObject(
+                        OpenApiConstants.UnevaluatedProperties,
+                        UnevaluatedPropertiesSchema,
+                        (w, s) => s.SerializeAsV31(w));
+                }
+                else if (!UnevaluatedProperties)
+                {
+                    writer.WriteProperty(OpenApiConstants.UnevaluatedProperties, UnevaluatedProperties);
+                }
             }
-            // true is the default, no need to write it out
             writer.WriteOptionalCollection(OpenApiConstants.Examples, Examples, (nodeWriter, s) => nodeWriter.WriteAny(s));
             writer.WriteOptionalMap(OpenApiConstants.PatternProperties, PatternProperties, (w, s) => s.SerializeAsV31(w));
             writer.WriteOptionalMap(OpenApiConstants.DependentRequired, DependentRequired, (w, s) => w.WriteValue(s));
@@ -827,19 +836,24 @@ private void SerializeAsV2(
             // x-nullable extension
             SerializeNullable(writer, OpenApiSpecVersion.OpenApi2_0);
 
-            // Write UnevaluatedPropertiesSchema as extension if present
-            if (UnevaluatedPropertiesSchema is not null)
+            // Write UnevaluatedPropertiesSchema as extension if present.
+            // Only emit when the type could include objects.
+            // Skip when type is explicitly set to a non-object type (array, string, number, integer, boolean, null).
+            if (!Type.HasValue || (Type.Value & JsonSchemaType.Object) != 0)
             {
-                writer.WriteOptionalObject(
-                    OpenApiConstants.UnevaluatedPropertiesExtension,
-                    UnevaluatedPropertiesSchema,
-                    (w, s) => s.SerializeAsV2(w));
-            }
-            // Write boolean false as extension if explicitly set to false
-            else if (!UnevaluatedProperties)
-            {
-                writer.WritePropertyName(OpenApiConstants.UnevaluatedPropertiesExtension);
-                writer.WriteValue(false);
+                if (UnevaluatedPropertiesSchema is not null)
+                {
+                    writer.WriteOptionalObject(
+                        OpenApiConstants.UnevaluatedPropertiesExtension,
+                        UnevaluatedPropertiesSchema,
+                        (w, s) => s.SerializeAsV2(w));
+                }
+                // Write boolean false as extension if explicitly set to false
+                else if (!UnevaluatedProperties)
+                {
+                    writer.WritePropertyName(OpenApiConstants.UnevaluatedPropertiesExtension);
+                    writer.WriteValue(false);
+                }
             }
 
             // Write patternProperties as an extension
diff --git a/test/Microsoft.OpenApi.Tests/Models/OpenApiSchemaTests.cs b/test/Microsoft.OpenApi.Tests/Models/OpenApiSchemaTests.cs
index 1e924cad3..c6a198918 100644
--- a/test/Microsoft.OpenApi.Tests/Models/OpenApiSchemaTests.cs
+++ b/test/Microsoft.OpenApi.Tests/Models/OpenApiSchemaTests.cs
@@ -1308,6 +1308,111 @@ public async Task SerializeUnevaluatedPropertiesTrueNotEmittedInEarlierVersions(
             Assert.True(JsonNode.DeepEquals(JsonNode.Parse(expected), JsonNode.Parse(actual)));
         }
 
+        [Theory]
+        [InlineData(JsonSchemaType.Array, "array")]
+        [InlineData(JsonSchemaType.String, "string")]
+        [InlineData(JsonSchemaType.Number, "number")]
+        [InlineData(JsonSchemaType.Integer, "integer")]
+        [InlineData(JsonSchemaType.Boolean, "boolean")]
+        [InlineData(JsonSchemaType.Null, "null")]
+        public async Task SerializeUnevaluatedPropertiesFalseNotEmittedForNonObjectType(JsonSchemaType nonObjectType, string typeName)
+        {
+            var expected = $@"{{ ""type"": ""{typeName}"" }}";
+            // Given - unevaluatedProperties should not be emitted when type is explicitly set to a non-object type
+            var schema = new OpenApiSchema
+            {
+                Type = nonObjectType,
+                UnevaluatedProperties = false
+            };
+
+            // When
+            var actual = await schema.SerializeAsJsonAsync(OpenApiSpecVersion.OpenApi3_1);
+
+            // Then
+            Assert.True(JsonNode.DeepEquals(JsonNode.Parse(expected), JsonNode.Parse(actual)));
+        }
+
+        [Theory]
+        [InlineData(JsonSchemaType.Array, "array")]
+        [InlineData(JsonSchemaType.String, "string")]
+        [InlineData(JsonSchemaType.Number, "number")]
+        [InlineData(JsonSchemaType.Integer, "integer")]
+        [InlineData(JsonSchemaType.Boolean, "boolean")]
+        [InlineData(JsonSchemaType.Null, "null")]
+        public async Task SerializeUnevaluatedPropertiesSchemaNotEmittedForNonObjectType(JsonSchemaType nonObjectType, string typeName)
+        {
+            var expected = $@"{{ ""type"": ""{typeName}"" }}";
+            // Given - unevaluatedProperties schema should not be emitted when type is explicitly set to a non-object type
+            var schema = new OpenApiSchema
+            {
+                Type = nonObjectType,
+                UnevaluatedPropertiesSchema = new OpenApiSchema { Type = JsonSchemaType.String }
+            };
+
+            // When
+            var actual = await schema.SerializeAsJsonAsync(OpenApiSpecVersion.OpenApi3_1);
+
+            // Then
+            Assert.True(JsonNode.DeepEquals(JsonNode.Parse(expected), JsonNode.Parse(actual)));
+        }
+
+        [Theory]
+        [InlineData(OpenApiSpecVersion.OpenApi2_0, JsonSchemaType.Array)]
+        [InlineData(OpenApiSpecVersion.OpenApi2_0, JsonSchemaType.String)]
+        [InlineData(OpenApiSpecVersion.OpenApi3_0, JsonSchemaType.Array)]
+        [InlineData(OpenApiSpecVersion.OpenApi3_0, JsonSchemaType.String)]
+        public async Task SerializeUnevaluatedPropertiesNotEmittedAsExtensionForNonObjectType(OpenApiSpecVersion version, JsonSchemaType nonObjectType)
+        {
+            // Given - unevaluatedProperties should not be emitted as extension when type is a non-object type
+            var schema = new OpenApiSchema
+            {
+                Type = nonObjectType,
+                UnevaluatedProperties = false
+            };
+
+            // When
+            var actual = await schema.SerializeAsJsonAsync(version);
+
+            // Then - should not contain unevaluatedProperties extension
+            var parsed = JsonNode.Parse(actual)!.AsObject();
+            Assert.False(parsed.ContainsKey(OpenApiConstants.UnevaluatedPropertiesExtension));
+        }
+
+        [Fact]
+        public async Task SerializeUnevaluatedPropertiesFalseStillEmittedForObjectType()
+        {
+            var expected = @"{ ""type"": ""object"", ""unevaluatedProperties"": false }";
+            // Given - unevaluatedProperties should still be emitted for object type
+            var schema = new OpenApiSchema
+            {
+                Type = JsonSchemaType.Object,
+                UnevaluatedProperties = false
+            };
+
+            // When
+            var actual = await schema.SerializeAsJsonAsync(OpenApiSpecVersion.OpenApi3_1);
+
+            // Then
+            Assert.True(JsonNode.DeepEquals(JsonNode.Parse(expected), JsonNode.Parse(actual)));
+        }
+
+        [Fact]
+        public async Task SerializeUnevaluatedPropertiesFalseStillEmittedWhenTypeNotSet()
+        {
+            var expected = @"{ ""unevaluatedProperties"": false }";
+            // Given - unevaluatedProperties should still be emitted when type is not explicitly set
+            var schema = new OpenApiSchema
+            {
+                UnevaluatedProperties = false
+            };
+
+            // When
+            var actual = await schema.SerializeAsJsonAsync(OpenApiSpecVersion.OpenApi3_1);
+
+            // Then
+            Assert.True(JsonNode.DeepEquals(JsonNode.Parse(expected), JsonNode.Parse(actual)));
+        }
+
         // PatternProperties tests
         [Theory]
         [InlineData(OpenApiSpecVersion.OpenApi3_1)]