diff --git a/src/components/tooltip/NetworkMarker.tsx b/src/components/tooltip/NetworkMarker.tsx
index 9ab033579b..c7f231c6c3 100644
--- a/src/components/tooltip/NetworkMarker.tsx
+++ b/src/components/tooltip/NetworkMarker.tsx
@@ -308,6 +308,14 @@ export function getNetworkMarkerDetails(
     </TooltipDetail>
   );
 
+  if (payload.priorityHeader) {
+    details.push(
+      <TooltipDetail label="Priority Header" key="Network-Priority-Header">
+        {payload.priorityHeader}
+      </TooltipDetail>
+    );
+  }
+
   if (mimeType) {
     details.push(
       <TooltipDetail label={mimeTypeLabel} key={'Network-' + mimeTypeLabel}>
diff --git a/src/types/markers.ts b/src/types/markers.ts
index 363dcdeeaf..f5113a889f 100644
--- a/src/types/markers.ts
+++ b/src/types/markers.ts
@@ -500,6 +500,9 @@ export type NetworkPayload = {
   RedirectURI?: string;
   id: number;
   pri: number; // priority of the load; always included as it can change
+  // The Priority header value from the HTTP response.
+  // This property is optional because older versions of Gecko do not include it.
+  priorityHeader?: string;
   count?: number; // Total size of transfer, if any
   // See all possible values in tools/profiler/core/platform.cpp
   status: NetworkStatus;