diff --git a/.changeset/gemini-live-property-ordering.md b/.changeset/gemini-live-property-ordering.md
new file mode 100644
index 000000000..30b10d04d
--- /dev/null
+++ b/.changeset/gemini-live-property-ordering.md
@@ -0,0 +1,5 @@
+---
+'@livekit/agents-plugin-google': patch
+---
+
+Send `propertyOrdering` in Gemini Live tool schemas so tool arguments are generated in declared order.
diff --git a/plugins/google/src/utils.test.ts b/plugins/google/src/utils.test.ts
index c1691a8f0..f33e3d546 100644
--- a/plugins/google/src/utils.test.ts
+++ b/plugins/google/src/utils.test.ts
@@ -56,10 +56,29 @@ describe('Gemini function declarations', () => {
     expect(declaration.parameters).toEqual({
       type: 'object',
       properties: { fields: { type: 'object' } },
+      propertyOrdering: ['fields'],
       required: ['fields'],
     });
   });
 
+  it('keeps declared property order on the Live API, nested objects included', () => {
+    const decide = llm.tool({
+      name: 'decide',
+      description: 'Reason first, then answer.',
+      parameters: z.object({
+        reasoning: z.string(),
+        answer: z.enum(['a', 'b']),
+        detail: z.object({ why: z.string(), confidence: z.number() }),
+      }),
+      execute: async () => {},
+    });
+    const parameters = singleDeclaration(new llm.ToolContext([decide]), false).parameters!;
+
+    expect(parameters.propertyOrdering).toEqual(['reasoning', 'answer', 'detail']);
+    expect(parameters.properties!.detail!.propertyOrdering).toEqual(['why', 'confidence']);
+    expect(parameters.properties!.reasoning!.propertyOrdering).toBeUndefined();
+  });
+
   it('omits the schema for a function tool without parameters', () => {
     const toolCtx = new llm.ToolContext([ping]);
     const textDeclaration = singleDeclaration(toolCtx);
diff --git a/plugins/google/src/utils.ts b/plugins/google/src/utils.ts
index a004e4ffa..c1e2dd788 100644
--- a/plugins/google/src/utils.ts
+++ b/plugins/google/src/utils.ts
@@ -81,6 +81,10 @@ export function convertJSONSchemaToOpenAPISchema(jsonSchema: JSONSchema7Definiti
       },
       {} as Record<string, unknown>,
     );
+    // Gemini generates an OpenAPI schema's properties alphabetically unless told
+    // otherwise; keep the declared order so earlier fields can inform later ones.
+    const keys = Object.keys(properties);
+    if (keys.length > 0) result.propertyOrdering = keys;
   }
 
   if (items) {