diff --git a/.chronus/changes/fix-symbol-decorator-state-display-2026-02-02-13-19-46.md b/.chronus/changes/fix-symbol-decorator-state-display-2026-02-02-13-19-46.md
new file mode 100644
index 00000000000..18c593935c8
--- /dev/null
+++ b/.chronus/changes/fix-symbol-decorator-state-display-2026-02-02-13-19-46.md
@@ -0,0 +1,7 @@
+---
+changeKind: fix
+packages:
+  - "@typespec/html-program-viewer"
+---
+
+Fix type graph viewer to display Symbol-keyed decorator state
diff --git a/packages/html-program-viewer/src/react/js-inspector/object-inspector.tsx b/packages/html-program-viewer/src/react/js-inspector/object-inspector.tsx
index b5bf0f4af58..e0b4817fea9 100644
--- a/packages/html-program-viewer/src/react/js-inspector/object-inspector.tsx
+++ b/packages/html-program-viewer/src/react/js-inspector/object-inspector.tsx
@@ -33,19 +33,25 @@ const createIterator = (showNonenumerable?: boolean, sortObjectKeys?: boolean) =
         i++;
       }
     } else {
-      const keys = Object.getOwnPropertyNames(data);
-      if (sortObjectKeys === true && !dataIsArray) {
+      // Get all property keys (both string and Symbol)
+      const stringKeys = Object.getOwnPropertyNames(data);
+      const symbolKeys = Object.getOwnPropertySymbols(data);
+      const allKeys: (string | symbol)[] = [...stringKeys, ...symbolKeys];
+
+      if (sortObjectKeys && !dataIsArray) {
         // Array keys should not be sorted in alphabetical order
-        keys.sort();
-      } else if (typeof sortObjectKeys === "function") {
-        keys.sort(sortObjectKeys);
+        allKeys.sort((a, b) => {
+          const aStr = typeof a === "string" ? a : a.toString();
+          const bStr = typeof b === "string" ? b : b.toString();
+          return aStr.localeCompare(bStr);
+        });
       }
 
-      for (const propertyName of keys) {
-        if (propertyIsEnumerable.call(data, propertyName)) {
-          const propertyValue = getPropertyValue(data, propertyName);
+      for (const key of allKeys) {
+        if (propertyIsEnumerable.call(data, key)) {
+          const propertyValue = getPropertyValue(data, key);
           yield {
-            name: propertyName || `""`,
+            name: typeof key === "string" ? key || `""` : key.toString(),
             data: propertyValue,
           };
         } else if (showNonenumerable) {
@@ -54,14 +60,14 @@ const createIterator = (showNonenumerable?: boolean, sortObjectKeys?: boolean) =
           // http://stackoverflow.com/questions/31921189/caller-and-arguments-are-restricted-function-properties-and-cannot-be-access
           let propertyValue;
           try {
-            propertyValue = getPropertyValue(data, propertyName);
+            propertyValue = getPropertyValue(data, key);
           } catch (e) {
             // console.warn(e)
           }
 
           if (propertyValue !== undefined) {
             yield {
-              name: propertyName,
+              name: typeof key === "string" ? key || `""` : key.toString(),
               data: propertyValue,
               isNonenumerable: true,
             };
diff --git a/packages/html-program-viewer/src/react/js-inspector/object-preview.tsx b/packages/html-program-viewer/src/react/js-inspector/object-preview.tsx
index f5e0a98b6fb..6e2ca37c124 100644
--- a/packages/html-program-viewer/src/react/js-inspector/object-preview.tsx
+++ b/packages/html-program-viewer/src/react/js-inspector/object-preview.tsx
@@ -4,7 +4,7 @@ import { JsValue } from "./js-value/js-value.js";
 import { ObjectName } from "./object-name.js";
 
 import style from "./object-inspector.module.css";
-import { hasOwnProperty } from "./utils/object-prototype.js";
+import { hasOwnProperty, propertyIsEnumerable } from "./utils/object-prototype.js";
 import { getPropertyValue } from "./utils/property-utils.js";
 
 /* intersperse arr with separator */
@@ -54,27 +54,36 @@ export const ObjectPreview: FC<any> = ({ data }) => {
   } else {
     const maxProperties = OBJECT_MAX_PROPERTIES;
     const propertyNodes: ReactNode[] = [];
-    for (const propertyName in object) {
-      if (hasOwnProperty.call(object, propertyName)) {
-        let ellipsis;
-        if (
-          propertyNodes.length === maxProperties - 1 &&
-          Object.keys(object).length > maxProperties
-        ) {
-          ellipsis = <span key={"ellipsis"}>…</span>;
-        }
-
-        const propertyValue = getPropertyValue(object, propertyName);
-        propertyNodes.push(
-          <span key={propertyName}>
-            <ObjectName name={propertyName || `""`} />
-            :&nbsp;
-            <JsValue value={propertyValue} />
-            {ellipsis}
-          </span>,
-        );
-        if (ellipsis) break;
+    
+    // Get all property keys (both string and Symbol), filtering for enumerable ones
+    const stringKeys = Object.keys(object); // Object.keys only returns enumerable string properties
+    const symbolKeys = Object.getOwnPropertySymbols(object).filter(sym => 
+      propertyIsEnumerable.call(object, sym)
+    );
+    const allKeys: (string | symbol)[] = [...stringKeys, ...symbolKeys];
+    const totalProperties = allKeys.length;
+    
+    for (let i = 0; i < allKeys.length; i++) {
+      const key = allKeys[i];
+      let ellipsis;
+      if (
+        propertyNodes.length === maxProperties - 1 &&
+        totalProperties > maxProperties
+      ) {
+        ellipsis = <span key={"ellipsis"}>…</span>;
       }
+
+      const propertyValue = getPropertyValue(object, key);
+      const displayName = typeof key === "string" ? key || `""` : key.toString();
+      propertyNodes.push(
+        <span key={typeof key === "string" ? key : `symbol-${i}`}>
+          <ObjectName name={displayName} />
+          :&nbsp;
+          <JsValue value={propertyValue} />
+          {ellipsis}
+        </span>,
+      );
+      if (ellipsis) break;
     }
 
     const objectConstructorName = object.constructor ? object.constructor.name : "Object";
diff --git a/packages/html-program-viewer/src/react/js-inspector/utils/property-utils.tsx b/packages/html-program-viewer/src/react/js-inspector/utils/property-utils.tsx
index 614e3975b2c..b87dc15df2a 100644
--- a/packages/html-program-viewer/src/react/js-inspector/utils/property-utils.tsx
+++ b/packages/html-program-viewer/src/react/js-inspector/utils/property-utils.tsx
@@ -1,4 +1,4 @@
-export function getPropertyValue(object: any, propertyName: string) {
+export function getPropertyValue(object: any, propertyName: string | symbol) {
   const propertyDescriptor = Object.getOwnPropertyDescriptor(object, propertyName);
   if (propertyDescriptor?.get) {
     try {