diff --git a/browser/components/asrouter/docs/targeting-attributes.md b/browser/components/asrouter/docs/targeting-attributes.md
index bc24acf93ba0..56ffcb24de36 100644
--- a/browser/components/asrouter/docs/targeting-attributes.md
+++ b/browser/components/asrouter/docs/targeting-attributes.md
@@ -61,6 +61,7 @@ Please note that some targeting attributes require stricter controls on the tele
 * [messageImpressions](#messageimpressions)
 * [needsUpdate](#needsupdate)
 * [newtabSettings](#newtabsettings)
+* [packageFamilyName](#packagefamilyname)
 * [pinnedSites](#pinnedsites)
 * [platformName](#platformname)
 * [previousSessionEnd](#previoussessionend)
@@ -371,6 +372,21 @@ Does the client have the latest available version installed
 declare const needsUpdate: boolean;
 ```
 
+### `packageFamilyName`
+Provides the package family name as given by the MSIX that Firefox was
+installed from, or the empty string if not installed from MSIX.
+
+#### Examples
+* Is the user running MSIX Nightly?
+```ts
+"MozillaNightly" in packageFamilyName
+```
+
+#### Definition
+```ts
+declare const packageFamilyName: string;
+```
+
 ### `pinnedSites`
 The sites (including search shortcuts) that are pinned on a user's new tab page.
 
diff --git a/browser/components/asrouter/modules/ASRouterTargeting.sys.mjs b/browser/components/asrouter/modules/ASRouterTargeting.sys.mjs
index d7d7aa1f5231..cd86ef09fa88 100644
--- a/browser/components/asrouter/modules/ASRouterTargeting.sys.mjs
+++ b/browser/components/asrouter/modules/ASRouterTargeting.sys.mjs
@@ -975,6 +975,22 @@ const TargetingGetters = {
     return Services.sysinfo.getProperty("hasWinPackageId", false);
   },
 
+  get packageFamilyName() {
+    if (AppConstants.platform !== "win") {
+      // PackageFamilyNames are an MSIX feature, so they won't be available on non-Windows platforms.
+      return null;
+    }
+
+    let packageFamilyName = Services.sysinfo.getProperty(
+      "winPackageFamilyName"
+    );
+    if (packageFamilyName === "") {
+      return null;
+    }
+
+    return packageFamilyName;
+  },
+
   /**
    * Is this invocation running in background task mode?
    *
diff --git a/browser/components/asrouter/tests/browser/browser_asrouter_targeting.js b/browser/components/asrouter/tests/browser/browser_asrouter_targeting.js
index 9dc2dada05ce..fb3a166eca1b 100644
--- a/browser/components/asrouter/tests/browser/browser_asrouter_targeting.js
+++ b/browser/components/asrouter/tests/browser/browser_asrouter_targeting.js
@@ -1570,6 +1570,64 @@ add_task(async function check_isMSIX() {
   );
 });
 
+add_task(async function check_packageFamilyName() {
+  if (AppConstants.platform !== "win") {
+    is(
+      ASRouterTargeting.Environment.packageFamilyName,
+      null,
+      "Should always be null on non-Windows"
+    );
+    return;
+  }
+
+  let winPackageFamilyName = Services.sysinfo.getProperty(
+    "winPackageFamilyName"
+  );
+  if (winPackageFamilyName === "") {
+    is(
+      ASRouterTargeting.Environment.packageFamilyName,
+      null,
+      "Should be null if sysinfo is empty"
+    );
+  } else {
+    is(
+      ASRouterTargeting.Environment.packageFamilyName,
+      winPackageFamilyName,
+      "Should match non-empty sysinfo"
+    );
+  }
+});
+
+add_task(async function check_msixConsistency() {
+  if (ASRouterTargeting.Environment.isMSIX) {
+    Assert.greater(
+      ASRouterTargeting.Environment.packageFamilyName.length,
+      0,
+      "packageFamilyName should be non-empty if installed by MSIX"
+    );
+  } else {
+    is(
+      ASRouterTargeting.Environment.packageFamilyName,
+      null,
+      "packageFamilyName should be empty if not installed by MSIX"
+    );
+  }
+
+  if (ASRouterTargeting.Environment.packageFamilyName === null) {
+    is(
+      ASRouterTargeting.Environment.isMSIX,
+      false,
+      "isMSIX should be false if packageFamilyName is not present"
+    );
+  } else {
+    is(
+      ASRouterTargeting.Environment.isMSIX,
+      true,
+      "isMSIX should be true if packageFamilyName is present"
+    );
+  }
+});
+
 add_task(async function check_isRTAMO() {
   is(
     typeof ASRouterTargeting.Environment.isRTAMO,