diff --git a/browser/components/extensions/parent/ext-sidebarAction.js b/browser/components/extensions/parent/ext-sidebarAction.js
index 27e65a15b3c5..a16d33267c9c 100644
--- a/browser/components/extensions/parent/ext-sidebarAction.js
+++ b/browser/components/extensions/parent/ext-sidebarAction.js
@@ -108,6 +108,10 @@ this.sidebarAction = class extends ExtensionAPI {
       if (SidebarUI.currentID === this.id) {
         SidebarUI.hide();
       }
+      if (SidebarUI.lastOpenedId === this.id &&
+          reason === "ADDON_UNINSTALL") {
+        SidebarUI.lastOpenedId = null;
+      }
       let menu = document.getElementById(this.menuId);
       if (menu) {
         menu.remove();
@@ -135,7 +139,8 @@ this.sidebarAction = class extends ExtensionAPI {
     for (let window of windowTracker.browserWindows()) {
       this.updateWindow(window);
       let {SidebarUI} = window;
-      if (install || SidebarUI.lastOpenedId == this.id) {
+      if ((install && this.extension.manifest.sidebar_action.open_at_install) ||
+          SidebarUI.lastOpenedId == this.id) {
         SidebarUI.show(this.id);
       }
     }
diff --git a/browser/components/extensions/schemas/sidebar_action.json b/browser/components/extensions/schemas/sidebar_action.json
index ae13737bda38..24ade0b0af33 100644
--- a/browser/components/extensions/schemas/sidebar_action.json
+++ b/browser/components/extensions/schemas/sidebar_action.json
@@ -30,6 +30,12 @@
                 "type": "string",
                 "format": "strictRelativeUrl",
                 "preprocess": "localize"
+              },
+              "open_at_install": {
+                "type": "boolean",
+                "optional": true,
+                "default": true,
+                "description": "Whether or not the sidebar is opened at install. Default is <code>true</code>."
               }
             },
             "optional": true
diff --git a/browser/components/extensions/test/browser/browser_ext_sidebarAction.js b/browser/components/extensions/test/browser/browser_ext_sidebarAction.js
index 0375533adfa9..280360e917d8 100644
--- a/browser/components/extensions/test/browser/browser_ext_sidebarAction.js
+++ b/browser/components/extensions/test/browser/browser_ext_sidebarAction.js
@@ -70,8 +70,8 @@ add_task(async function sidebar_initial_install() {
   ok(document.getElementById("sidebar-box").hidden, "sidebar box is not visible");
   let extension = ExtensionTestUtils.loadExtension(getExtData());
   await extension.startup();
+
   // Test sidebar is opened on install
-  await extension.awaitMessage("sidebar");
   ok(!document.getElementById("sidebar-box").hidden, "sidebar box is visible");
 
   await extension.unload();
@@ -79,6 +79,20 @@ add_task(async function sidebar_initial_install() {
   ok(document.getElementById("sidebar-box").hidden, "sidebar box is not visible");
 });
 
+add_task(async function sidebar__install_closed() {
+  ok(document.getElementById("sidebar-box").hidden, "sidebar box is not visible");
+  let tempExtData = getExtData();
+  tempExtData.manifest.sidebar_action.open_at_install = false;
+  let extension = ExtensionTestUtils.loadExtension(tempExtData);
+  await extension.startup();
+
+  // Test sidebar is closed on install
+  ok(document.getElementById("sidebar-box").hidden, "sidebar box is hidden");
+
+  await extension.unload();
+  // This is the default value
+  tempExtData.manifest.sidebar_action.open_at_install = true;
+});
 
 add_task(async function sidebar_two_sidebar_addons() {
   let extension2 = ExtensionTestUtils.loadExtension(getExtData());