--- a/devtools/client/netmonitor/src/connector/index.js
+++ b/devtools/client/netmonitor/src/connector/index.js
@@ -507,24 +507,30 @@ class Connector {
 
     const state = this.getState();
     return getDisplayedTimingMarker(state, name);
   }
 
   async updateNetworkThrottling(enabled, profile) {
     if (!enabled) {
       this.networkFront.clearNetworkThrottling();
+      await this.commands.targetConfigurationCommand.updateConfiguration({
+        setTabOffline: false,
+      });
     } else {
       // The profile can be either a profile id which is used to
       // search the predefined throttle profiles or a profile object
       // as defined in the trottle tests.
       if (typeof profile === "string") {
         profile = throttlingProfiles.find(({ id }) => id == profile);
       }
       const { download, upload, latency } = profile;
+      await this.commands.targetConfigurationCommand.updateConfiguration({
+        setTabOffline: !download,
+      });
       await this.networkFront.setNetworkThrottling({
         downloadThroughput: download,
         uploadThroughput: upload,
         latency,
       });
     }
 
     this.emitForTests(TEST_EVENTS.THROTTLING_CHANGED, { profile });

--- a/devtools/client/shared/components/throttling/profiles.js
+++ b/devtools/client/shared/components/throttling/profiles.js
@@ -94,11 +94,17 @@ const profiles = [
     latency: 5,
   },
   {
     id: "Wi-Fi",
     download: 30 * MBps,
     upload: 15 * MBps,
     latency: 2,
   },
+  {
+    id: "Offline",
+    download: 0,
+    upload: 0,
+    latency: 5,
+  },
 ].map(profile => new ThrottlingProfile(profile));
 
 module.exports = profiles;

--- a/devtools/docs/user/network_monitor/throttling/index.rst
+++ b/devtools/docs/user/network_monitor/throttling/index.rst
@@ -27,16 +27,17 @@ The table below lists the numbers associ
   GPRS, 50 Kbps, 20 Kbps, 500
   Regular 2G, 250 Kbps, 50 Kbps, 300
   Good 2G, 450 Kbps, 150 Kbps, 150
   Regular 3G, 750 Kbps, 250 Kbps, 100
   Good 3G, 1.5 Mbps, 750 Kbps, 40
   Regular 4G/LTE, 4 Mbps, 3 Mbps, 20
   DSL, 2 Mbps, 1 Mbps, 5
   Wi-Fi, 30 Mbps, 15 Mbps, 2
+  Offline, 0 Mbps, 0 Mbps, 5
 
 Network Monitor Features
 ************************
 
 The following articles cover different aspects of using the network monitor:
 
 - :doc:`Toolbar <../toolbar/index>`
 - :doc:`Network request list <../request_list/index>`

--- a/devtools/docs/user/responsive_design_mode/index.rst
+++ b/devtools/docs/user/responsive_design_mode/index.rst
@@ -197,12 +197,17 @@ The table below lists the numbers associ
     - 1 Mb/s
     - 5
 
   * - Wi-Fi
     - 30 Mb/s
     - 15 Mb/s
     - 2
 
+  * - Offline
+    - 0 Mb/s
+    - 0 Mb/s
+    - 5
+
 To select a network, click the list box that's initially labeled "No throttling":
 
 .. image:: rdm_throttling.png
   :class: center

--- a/devtools/server/actors/target-configuration.js
+++ b/devtools/server/actors/target-configuration.js
@@ -42,16 +42,18 @@ const SUPPORTED_OPTIONS = {
   // Enable allocation tracking, if set, contains an object defining the tracking configurations
   recordAllocations: true,
   // Reload the page when the touch simulation state changes (only works alongside touchEventsOverride)
   reloadOnTouchSimulationToggle: true,
   // Restore focus in the page after closing DevTools.
   restoreFocus: true,
   // Enable service worker testing over HTTP (instead of HTTPS only).
   serviceWorkersTestingEnabled: true,
+  // Set the current tab offline
+  setTabOffline: true,
   // Enable touch events simulation
   touchEventsOverride: true,
   // Use simplified highlighters when prefers-reduced-motion is enabled.
   useSimpleHighlightersForReducedMotion: true,
 };
 /* eslint-disable sort-keys */
 
 /**
@@ -261,32 +263,36 @@ class TargetConfigurationActor extends A
           this._setServiceWorkersTestingEnabled(value);
           break;
         case "touchEventsOverride":
           this._setTouchEventsOverride(value);
           break;
         case "cacheDisabled":
           this._setCacheDisabled(value);
           break;
+        case "setTabOffline":
+          this._setTabOffline(value);
+          break;
       }
     }
 
     if (shouldReload) {
       this._browsingContext.reload(Ci.nsIWebNavigation.LOAD_FLAGS_NONE);
     }
   }
 
   _restoreParentProcessConfiguration() {
     if (!this._shouldHandleConfigurationInParentProcess()) {
       return;
     }
 
     this._setServiceWorkersTestingEnabled(false);
     this._setPrintSimulationEnabled(false);
     this._setCacheDisabled(false);
+    this._setTabOffline(false);
 
     // Restore the color scheme simulation only if it was explicitly updated
     // by this actor. This will avoid side effects caused when destroying additional
     // targets (e.g. RDM target, WebExtension target, …).
     // TODO: We may want to review other configuration values to see if we should use
     // the same pattern (Bug 1701553).
     if (this._resetColorSchemeSimulationOnDestroy) {
       this._setColorSchemeSimulation(null);
@@ -448,16 +454,27 @@ class TargetConfigurationActor extends A
     const value = disabled
       ? Ci.nsIRequest.LOAD_BYPASS_CACHE
       : Ci.nsIRequest.LOAD_NORMAL;
     if (this._browsingContext.defaultLoadFlags != value) {
       this._browsingContext.defaultLoadFlags = value;
     }
   }
 
+  /**
+   * Set the browsing context to offline.
+   *
+   * @param {Boolean} offline: Whether the network throttling is set to offline
+   */
+  _setTabOffline(offline) {
+    if (!this._browsingContext.isDiscarded) {
+      this._browsingContext.forceOffline = offline;
+    }
+  }
+
   destroy() {
     Services.obs.removeObserver(
       this._onBrowsingContextAttached,
       "browsing-context-attached"
     );
     this.watcherActor.off(
       "bf-cache-navigation-pageshow",
       this._onBfCacheNavigation

--- a/devtools/shared/commands/target-configuration/tests/browser_target_configuration_command.js
+++ b/devtools/shared/commands/target-configuration/tests/browser_target_configuration_command.js
@@ -57,16 +57,44 @@ add_task(async function () {
     {
       cacheDisabled: false,
       colorSchemeSimulation: "dark",
       javascriptEnabled: false,
     },
     "Option colorSchemeSimulation was set, with a string value"
   );
 
+  await targetConfigurationCommand.updateConfiguration({
+    setTabOffline: true,
+  });
+  compareOptions(
+    targetConfigurationCommand.configuration,
+    {
+      cacheDisabled: false,
+      colorSchemeSimulation: "dark",
+      javascriptEnabled: false,
+      setTabOffline: true,
+    },
+    "Option setTabOffline was set on"
+  );
+
+  await targetConfigurationCommand.updateConfiguration({
+    setTabOffline: false,
+  });
+  compareOptions(
+    targetConfigurationCommand.configuration,
+    {
+      setTabOffline: false,
+      cacheDisabled: false,
+      colorSchemeSimulation: "dark",
+      javascriptEnabled: false,
+    },
+    "Option setTabOffline was set off"
+  );
+
   targetCommand.destroy();
   await commands.destroy();
 });
 
 function compareOptions(options, expected, message) {
   is(
     Object.keys(options).length,
     Object.keys(expected).length,

--- a/devtools/shared/specs/target-configuration.js
+++ b/devtools/shared/specs/target-configuration.js
@@ -18,16 +18,17 @@ types.addDictType("target-configuration.
   customUserAgent: "nullable:string",
   javascriptEnabled: "nullable:boolean",
   overrideDPPX: "nullable:number",
   printSimulationEnabled: "nullable:boolean",
   rdmPaneOrientation: "nullable:json",
   reloadOnTouchSimulationToggle: "nullable:boolean",
   restoreFocus: "nullable:boolean",
   serviceWorkersTestingEnabled: "nullable:boolean",
+  setTabOffline: "nullable:boolean",
   touchEventsOverride: "nullable:string",
 });
 
 const targetConfigurationSpec = generateActorSpec({
   typeName: "target-configuration",
 
   methods: {
     updateConfiguration: {

--- a/toolkit/components/telemetry/Events.yaml
+++ b/toolkit/components/telemetry/Events.yaml
@@ -2348,17 +2348,17 @@ devtools.main:
     products:
       - "firefox"
       - "fennec"
     record_in_processes: ["main"]
     description: User has changed the throttle setting in the netmonitor.
     release_channel_collection: opt-out
     expiry_version: never
     extra_keys:
-      mode: No throttling, GPRS, Regular 2G, Good 2G, Regular 3G, Good 3G, Regular 4G / LTE, DSL or WI-FI.
+      mode: No throttling, GPRS, Regular 2G, Good 2G, Regular 3G, Good 3G, Regular 4G / LTE, DSL, WI-FI, or Offline.
       session_id: The toolbox session start time e.g. 13963.
   tool_timer:
     objects: ["animationinspector", "compatibilityview", "computedview", "changesview", "fontinspector", "layoutview", "ruleview"]
     bug_numbers: [1483817, 1639454]
     notification_emails: ["[email protected]"]
     products:
       - "firefox"
       - "fennec"