diff --git a/example/browser/index.html b/example/browser/index.html
index 6eba68fe..6116a752 100644
--- a/example/browser/index.html
+++ b/example/browser/index.html
@@ -13,7 +13,8 @@ <h1>Error Submission</h1>
     <button id="throw-string-error">Throw string error</button>
     <button id="throw-ignored-error">Throw ignored error</button>
     <button onclick="throwReferenceError('function-does-exist')">Throw uncaught reference error</button>
-    <button id="throw-jquery-ajax-error">Throw jquery ajax error</button>
+    <button id="throw-jquery-ajax-error">Throw jQuery ajax error</button>
+    <button id="throw-promise-unhandled-rejection">Throw promise unhandled rejection</button>
 
     <h1>Log Submission</h1>
     <button class="submit-log">Submit log event</button>
diff --git a/example/browser/index.js b/example/browser/index.js
index 40bfbcc1..59168aa9 100644
--- a/example/browser/index.js
+++ b/example/browser/index.js
@@ -95,6 +95,29 @@ document.addEventListener("DOMContentLoaded", () => {
       });
     });
 
+  document
+    .querySelector("#throw-promise-unhandled-rejection")
+    .addEventListener("click", () => {
+      const promiseFn = () => new Promise(function (_, reject) {
+        switch (Math.floor(Math.random() * 4)) {
+          case 0:
+            reject(0);
+            break;
+          case 1:
+            reject(new Error("Promise rejected error"));
+            break;
+          case 2:
+            reject("Promise rejected string");
+            break;
+          case 3:
+            reject();
+            break;
+        }
+      });
+
+      promiseFn();
+    });
+
   document
     .querySelector("#config-settings-log")
     .addEventListener("click", () => {
diff --git a/packages/browser/src/plugins/BrowserGlobalHandlerPlugin.ts b/packages/browser/src/plugins/BrowserGlobalHandlerPlugin.ts
index 73f86d6a..eb06a499 100644
--- a/packages/browser/src/plugins/BrowserGlobalHandlerPlugin.ts
+++ b/packages/browser/src/plugins/BrowserGlobalHandlerPlugin.ts
@@ -1,7 +1,8 @@
 import {
   ExceptionlessClient,
   IEventPlugin,
-  PluginContext
+  PluginContext,
+  toError
 } from "@exceptionless/core";
 
 declare let $: (document: Document) => { ajaxError: { (document: (event: Event, xhr: { responseText: string; status: number; }, settings: { data: unknown; url: string; }, error: string) => void): void; }; };
@@ -25,15 +26,16 @@ export class BrowserGlobalHandlerPlugin implements IEventPlugin {
     });
 
     window.addEventListener("unhandledrejection", event => {
-      let error = event.reason;
+      let reason: unknown = event.reason;
       try {
-        const reason = (<{ detail?: { reason: string} }>event).detail?.reason;
-        if (reason) {
-          error = reason;
+        const detailReason = (<{ detail?: { reason: string } }>event).detail?.reason;
+        if (detailReason) {
+          reason = detailReason;
         }
       } catch (ex) { /* empty */ }
 
-      void this._client?.submitUnhandledException(error as Error, "onunhandledrejection");
+      const error: Error = toError(reason, "Unhandled rejection")
+      void this._client?.submitUnhandledException(error, "onunhandledrejection");
     });
 
 
diff --git a/packages/core/src/Utils.ts b/packages/core/src/Utils.ts
index a260068f..55ad91b4 100644
--- a/packages/core/src/Utils.ts
+++ b/packages/core/src/Utils.ts
@@ -292,3 +292,19 @@ export function toBoolean(input: unknown, defaultValue: boolean = false): boolea
 
   return defaultValue;
 }
+
+export function toError(errorOrMessage: unknown, defaultMessage = "Unknown Error"): Error {
+  if (errorOrMessage === null || errorOrMessage === undefined) {
+    return new Error(defaultMessage);
+  }
+
+  if (errorOrMessage instanceof Error) {
+    return errorOrMessage;
+  }
+
+  if (typeof errorOrMessage === "string") {
+    return new Error(errorOrMessage);
+  }
+
+  return new Error(JSON.stringify(errorOrMessage) || defaultMessage);
+}
diff --git a/packages/core/src/index.ts b/packages/core/src/index.ts
index 337921da..2e88cf61 100644
--- a/packages/core/src/index.ts
+++ b/packages/core/src/index.ts
@@ -65,4 +65,5 @@ export {
   startsWith,
   stringify,
   toBoolean,
+  toError,
 } from "./Utils.js";
diff --git a/packages/node/src/plugins/NodeGlobalHandlerPlugin.ts b/packages/node/src/plugins/NodeGlobalHandlerPlugin.ts
index 73a41bf4..67bbfa3a 100644
--- a/packages/node/src/plugins/NodeGlobalHandlerPlugin.ts
+++ b/packages/node/src/plugins/NodeGlobalHandlerPlugin.ts
@@ -1,7 +1,8 @@
 import {
   ExceptionlessClient,
   IEventPlugin,
-  PluginContext
+  PluginContext,
+  toError
 } from "@exceptionless/core";
 
 export class NodeGlobalHandlerPlugin implements IEventPlugin {
@@ -23,7 +24,8 @@ export class NodeGlobalHandlerPlugin implements IEventPlugin {
     });
 
     process.addListener("unhandledRejection", (reason: unknown | null | undefined) => {
-      void this._client?.submitUnhandledException(<Error>reason, "unhandledRejection");
+      const error: Error = toError(reason, "Unhandled rejection")
+      void this._client?.submitUnhandledException(error, "unhandledRejection");
     });
 
     return Promise.resolve();

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