diff --git a/src/components/__tests__/__snapshots__/DiscriminatorDropdown.test.tsx.snap b/src/components/__tests__/__snapshots__/DiscriminatorDropdown.test.tsx.snap
index f43b92da..5cbc5e04 100644
--- a/src/components/__tests__/__snapshots__/DiscriminatorDropdown.test.tsx.snap
+++ b/src/components/__tests__/__snapshots__/DiscriminatorDropdown.test.tsx.snap
@@ -300,7 +300,6 @@ exports[`Components SchemaView discriminator should correctly render SchemaView
                   "pattern": undefined,
                   "pointer": "#/components/schemas/Dog/properties/packSize",
                   "rawSchema": {
-                    "default": undefined,
                     "type": "number",
                   },
                   "readOnly": false,
@@ -309,7 +308,6 @@ exports[`Components SchemaView discriminator should correctly render SchemaView
                     "#/components/schemas/Dog/properties/packSize",
                   ],
                   "schema": {
-                    "default": undefined,
                     "type": "number",
                   },
                   "title": "",
@@ -576,7 +574,6 @@ exports[`Components SchemaView discriminator should correctly render SchemaView
                   "pattern": undefined,
                   "pointer": "#/components/schemas/Dog/properties/type",
                   "rawSchema": {
-                    "default": undefined,
                     "type": "string",
                     "x-refsStack": [
                       "#/components/schemas/Dog",
@@ -593,7 +590,6 @@ exports[`Components SchemaView discriminator should correctly render SchemaView
                     "#/components/schemas/Dog/properties/type",
                   ],
                   "schema": {
-                    "default": undefined,
                     "type": "string",
                     "x-refsStack": [
                       "#/components/schemas/Dog",
@@ -1164,7 +1160,6 @@ exports[`Components SchemaView discriminator should correctly render SchemaView
                   "pattern": undefined,
                   "pointer": "#/components/schemas/Cat/properties/type",
                   "rawSchema": {
-                    "default": undefined,
                     "type": "string",
                     "x-refsStack": [
                       "#/components/schemas/Cat",
@@ -1181,7 +1176,6 @@ exports[`Components SchemaView discriminator should correctly render SchemaView
                     "#/components/schemas/Cat/properties/type",
                   ],
                   "schema": {
-                    "default": undefined,
                     "type": "string",
                     "x-refsStack": [
                       "#/components/schemas/Cat",
@@ -1452,7 +1446,6 @@ exports[`Components SchemaView discriminator should correctly render SchemaView
                   "pattern": undefined,
                   "pointer": "#/components/schemas/Cat/properties/packSize",
                   "rawSchema": {
-                    "default": undefined,
                     "type": "number",
                     "x-refsStack": [
                       "#/components/schemas/Cat",
@@ -1466,7 +1459,6 @@ exports[`Components SchemaView discriminator should correctly render SchemaView
                     "#/components/schemas/Cat/properties/packSize",
                   ],
                   "schema": {
-                    "default": undefined,
                     "type": "number",
                     "x-refsStack": [
                       "#/components/schemas/Cat",
@@ -2309,7 +2301,6 @@ exports[`Components SchemaView discriminator should correctly render SchemaView
             "pattern": undefined,
             "pointer": "#/components/schemas/Dog/properties/packSize",
             "rawSchema": {
-              "default": undefined,
               "type": "number",
             },
             "readOnly": false,
@@ -2318,7 +2309,6 @@ exports[`Components SchemaView discriminator should correctly render SchemaView
               "#/components/schemas/Dog/properties/packSize",
             ],
             "schema": {
-              "default": undefined,
               "type": "number",
             },
             "title": "",
@@ -2585,7 +2575,6 @@ exports[`Components SchemaView discriminator should correctly render SchemaView
             "pattern": undefined,
             "pointer": "#/components/schemas/Dog/properties/type",
             "rawSchema": {
-              "default": undefined,
               "type": "string",
               "x-refsStack": [
                 "#/components/schemas/Dog",
@@ -2602,7 +2591,6 @@ exports[`Components SchemaView discriminator should correctly render SchemaView
               "#/components/schemas/Dog/properties/type",
             ],
             "schema": {
-              "default": undefined,
               "type": "string",
               "x-refsStack": [
                 "#/components/schemas/Dog",
@@ -2945,7 +2933,6 @@ exports[`Components SchemaView discriminator should correctly render discriminat
             "pattern": undefined,
             "pointer": "#/components/schemas/Dog/properties/packSize",
             "rawSchema": {
-              "default": undefined,
               "type": "number",
             },
             "readOnly": false,
@@ -2954,7 +2941,6 @@ exports[`Components SchemaView discriminator should correctly render discriminat
               "#/components/schemas/Dog/properties/packSize",
             ],
             "schema": {
-              "default": undefined,
               "type": "number",
             },
             "title": "",
@@ -3008,7 +2994,6 @@ exports[`Components SchemaView discriminator should correctly render discriminat
             "pattern": undefined,
             "pointer": "#/components/schemas/Dog/properties/type",
             "rawSchema": {
-              "default": undefined,
               "type": "string",
               "x-refsStack": [
                 "#/components/schemas/Dog",
@@ -3025,7 +3010,6 @@ exports[`Components SchemaView discriminator should correctly render discriminat
               "#/components/schemas/Dog/properties/type",
             ],
             "schema": {
-              "default": undefined,
               "type": "string",
               "x-refsStack": [
                 "#/components/schemas/Dog",
diff --git a/src/services/__tests__/fixtures/oneOf.json b/src/services/__tests__/fixtures/oneOf.json
new file mode 100644
index 00000000..f02d9b3d
--- /dev/null
+++ b/src/services/__tests__/fixtures/oneOf.json
@@ -0,0 +1,40 @@
+{
+  "openapi": "3.0.0",
+  "info": {
+    "title": "Test",
+    "version": "1.0.0"
+  },
+  "components": {
+    "schemas": {
+      "Response": {
+        "type": "object",
+        "properties": {
+          "data": {
+            "$ref": "#/components/schemas/Data"
+          }
+        }
+      },
+      "Data": {
+        "type": "object",
+        "oneOf": [
+          { "$ref": "#/components/schemas/WithTitle" },
+          { "$ref": "#/components/schemas/NoTitle" },
+          {
+            "title": "InlineWithTitle",
+            "type": "object",
+            "properties": {
+              "inline": { "type": "string" }
+            }
+          }
+        ]
+      },
+      "WithTitle": {
+        "title": "ExplicitTitle",
+        "type": "object"
+      },
+      "NoTitle": {
+        "type": "object"
+      }
+    }
+  }
+}
diff --git a/src/services/__tests__/models/Schema.test.ts b/src/services/__tests__/models/Schema.test.ts
index 514599d9..13dc672a 100644
--- a/src/services/__tests__/models/Schema.test.ts
+++ b/src/services/__tests__/models/Schema.test.ts
@@ -56,6 +56,20 @@ describe('Models', () => {
       expect(schema.displayType).toBe('(Array of strings or numbers) or string');
     });
 
+    test('oneOf titles: explicit, inferred from $ref, and inline with title', () => {
+      const spec = require('../fixtures/oneOf.json');
+      parser = new OpenAPIParser(spec, undefined, opts);
+      const schema = new SchemaModel(parser, spec.components.schemas.Response, '', opts);
+
+      const dataField = schema.fields?.find(f => f.name === 'data');
+      expect(dataField).toBeDefined();
+      expect(dataField!.schema.oneOf).toHaveLength(3);
+
+      expect(dataField!.schema.oneOf![0].title).toBe('ExplicitTitle');
+      expect(dataField!.schema.oneOf![1].title).toBe('NoTitle');
+      expect(dataField!.schema.oneOf![2].title).toBe('InlineWithTitle');
+    });
+
     test('schemaDefinition should resolve double ref', () => {
       const spec = require('../fixtures/3.1/schemaDefinition.json');
       parser = new OpenAPIParser(spec, undefined, opts);
diff --git a/src/services/__tests__/models/__snapshots__/Schema.test.ts.snap b/src/services/__tests__/models/__snapshots__/Schema.test.ts.snap
index 4996ba0e..defc840c 100644
--- a/src/services/__tests__/models/__snapshots__/Schema.test.ts.snap
+++ b/src/services/__tests__/models/__snapshots__/Schema.test.ts.snap
@@ -3,7 +3,6 @@
 exports[`Models Schema schemaDefinition should resolve field with conditional operators 1`] = `
 {
   "allOf": undefined,
-  "default": undefined,
   "description": undefined,
   "items": {
     "allOf": undefined,
@@ -31,7 +30,6 @@ exports[`Models Schema schemaDefinition should resolve field with conditional op
 exports[`Models Schema schemaDefinition should resolve field with conditional operators 2`] = `
 {
   "allOf": undefined,
-  "default": undefined,
   "description": undefined,
   "items": {
     "allOf": undefined,
diff --git a/src/services/models/Schema.ts b/src/services/models/Schema.ts
index a07e0719..19638a56 100644
--- a/src/services/models/Schema.ts
+++ b/src/services/models/Schema.ts
@@ -447,6 +447,8 @@ function buildFields(
     const required =
       schema.required === undefined ? false : schema.required.indexOf(fieldName) > -1;
 
+    const defaultValue = field.default === undefined && defaults ? defaults[fieldName] : field.default;
+
     return new FieldModel(
       parser,
       {
@@ -454,7 +456,9 @@ function buildFields(
         required,
         schema: {
           ...field,
-          default: field.default === undefined && defaults ? defaults[fieldName] : field.default,
+          // Only include default if it has an actual value; adding `default: undefined`
+          // triggers allOf wrapping in OpenAPI 3.1's mergeRefs, breaking oneOf handling
+          ...(defaultValue !== undefined ? { default: defaultValue } : {}),
         },
       },
       $ref + '/properties/' + fieldName,