diff --git a/core/src/main/java/org/openapitools/openapidiff/core/compare/schemadiffresult/ComposedSchemaDiffResult.java b/core/src/main/java/org/openapitools/openapidiff/core/compare/schemadiffresult/ComposedSchemaDiffResult.java
index 077552e2a..ea681db13 100644
--- a/core/src/main/java/org/openapitools/openapidiff/core/compare/schemadiffresult/ComposedSchemaDiffResult.java
+++ b/core/src/main/java/org/openapitools/openapidiff/core/compare/schemadiffresult/ComposedSchemaDiffResult.java
@@ -6,6 +6,7 @@
 import io.swagger.v3.oas.models.media.Schema;
 import java.util.HashSet;
 import java.util.LinkedHashMap;
+import java.util.List;
 import java.util.Map;
 import java.util.Optional;
 import java.util.stream.Collectors;
@@ -63,7 +64,8 @@ public <T extends Schema<X>, X> Optional<ChangedSchema> diff(
 
         MapKeyDiff<String, Schema> mappingDiff =
             MapKeyDiff.diff(
-                getSchema(leftComponents, leftMapping), getSchema(rightComponents, rightMapping));
+                getSchema(leftComponents, leftMapping, leftComposedSchema),
+                getSchema(rightComponents, rightMapping, rightComposedSchema));
         Map<String, ChangedSchema> changedMapping = new LinkedHashMap<>();
         for (String key : mappingDiff.getSharedKey()) {
           Schema leftSchema = new Schema();
@@ -88,10 +90,14 @@ public <T extends Schema<X>, X> Optional<ChangedSchema> diff(
     }
   }
 
-  private Map<String, Schema> getSchema(Components components, Map<String, String> mapping) {
+  private Map<String, Schema> getSchema(Components components, Map<String, String> mapping, ComposedSchema composedSchema) {
     Map<String, Schema> result = new LinkedHashMap<>();
     mapping.forEach(
         (key, value) -> result.put(key, refPointer.resolveRef(components, new Schema(), value)));
+
+    result.putAll(getUnnamedSchemas(composedSchema.getAllOf(), "all-of"));
+    result.putAll(getUnnamedSchemas(composedSchema.getOneOf(), "one-of"));
+    result.putAll(getUnnamedSchemas(composedSchema.getAnyOf(), "any-of"));
     return result;
   }
 
@@ -100,7 +106,7 @@ private Map<String, String> getMapping(ComposedSchema composedSchema) {
     for (Schema schema : composedSchema.getOneOf()) {
       String ref = schema.get$ref();
       if (ref == null) {
-        throw new IllegalArgumentException("invalid oneOf schema");
+          continue;
       }
       String schemaName = refPointer.getRefName(ref);
       if (schemaName == null) {
@@ -119,4 +125,25 @@ private Map<String, String> getMapping(ComposedSchema composedSchema) {
     return reverseMapping.entrySet().stream()
         .collect(Collectors.toMap(Map.Entry::getValue, Map.Entry::getKey));
   }
+
+  private Map<String, Schema> getUnnamedSchemas(List<Schema> schemas, String name) {
+    Map<String, Schema> result = new LinkedHashMap<>();
+
+    if (schemas == null) {
+      return result;
+    }
+
+    for (int i = 0; i < schemas.size(); i++) {
+      Schema schema = schemas.get(i);
+
+      // If the ref is named, then we ignore it since getMapping will handle it.
+      if (schema.get$ref() != null) {
+        continue;
+      }
+
+      result.put(String.format("%s-%s", name, i), schema);
+    }
+
+    return result;
+  }
 }
diff --git a/core/src/test/java/org/openapitools/openapidiff/core/OneOfDiffTest.java b/core/src/test/java/org/openapitools/openapidiff/core/OneOfDiffTest.java
index 236faa717..cf893c588 100644
--- a/core/src/test/java/org/openapitools/openapidiff/core/OneOfDiffTest.java
+++ b/core/src/test/java/org/openapitools/openapidiff/core/OneOfDiffTest.java
@@ -18,6 +18,7 @@ public class OneOfDiffTest {
   private final String OPENAPI_DOC7 = "oneOf_discriminator-changed_2.yaml";
   private final String OPENAPI_DOC8 = "oneOf_discriminator-missing_1.yaml";
   private final String OPENAPI_DOC9 = "oneOf_discriminator-missing_2.yaml";
+  private final String OPENAPI_DOC10 = "unnamed_oneof_schema_1.yaml";
 
   @Test
   public void testDiffSame() {
@@ -39,6 +40,10 @@ public void testComposedSchema() {
     assertOpenApiBackwardIncompatible(OPENAPI_DOC4, OPENAPI_DOC5);
   }
 
+  @Test
+  public void testComposedSchemaDiff() {
+    assertOpenApiAreEquals(OPENAPI_DOC10, OPENAPI_DOC10);
+  }
   @Test
   public void testOneOfDiscrimitatorChanged() {
     // The oneOf 'discriminator' changed: 'realtype' -> 'othertype':
diff --git a/core/src/test/resources/unnamed_oneof_schema_1.yaml b/core/src/test/resources/unnamed_oneof_schema_1.yaml
new file mode 100644
index 000000000..947757ee2
--- /dev/null
+++ b/core/src/test/resources/unnamed_oneof_schema_1.yaml
@@ -0,0 +1,22 @@
+openapi: 3.0.0
+info:
+  title: Test Service
+  version: 1.0.0
+paths:
+  /test:
+    get:
+      responses:
+        "200":
+          description: Success
+          content:
+            application/json:
+              schema:
+                oneOf:
+                  - type: object
+                    properties:
+                      name:
+                        type: string
+                  - type: object
+                    properties:
+                      name:
+                        type: number
\ No newline at end of file