diff --git a/app/assets/javascripts/discourse/app/components/d-modal.hbs b/app/assets/javascripts/discourse/app/components/d-modal.hbs
index 5d9d1ce0077..fcb28cf6b2a 100644
--- a/app/assets/javascripts/discourse/app/components/d-modal.hbs
+++ b/app/assets/javascripts/discourse/app/components/d-modal.hbs
@@ -34,15 +34,19 @@
             />
           {{/if}}
 
-          {{#if this.title}}
-            <div class="title">
-              <h3 id="discourse-modal-title">{{this.title}}</h3>
+          <div class="modal-title-wrapper">
+            {{#if this.title}}
+              <div class="title">
+                <h3 id="discourse-modal-title">{{this.title}}</h3>
 
-              {{#if this.subtitle}}
-                <p class="subtitle">{{this.subtitle}}</p>
-              {{/if}}
-            </div>
-          {{/if}}
+                {{#if this.subtitle}}
+                  <p class="subtitle">{{this.subtitle}}</p>
+                {{/if}}
+              </div>
+            {{/if}}
+
+            <span id="modal-header-after-title"></span>
+          </div>
 
           {{#if this.panels}}
             <ul class="modal-tabs">
diff --git a/app/assets/javascripts/discourse/app/components/sidebar/categories-form-modal.hbs b/app/assets/javascripts/discourse/app/components/sidebar/categories-form-modal.hbs
index a1052778657..988eab9b7e1 100644
--- a/app/assets/javascripts/discourse/app/components/sidebar/categories-form-modal.hbs
+++ b/app/assets/javascripts/discourse/app/components/sidebar/categories-form-modal.hbs
@@ -1,75 +1,102 @@
-<DModalBody
-  @title="sidebar.categories_form.title"
-  @class="sidebar-categories-form-modal"
->
-  <form class="sidebar-categories-form">
-    <div class="sidebar-categories-form__filter">
-      {{d-icon "search" class="sidebar-categories-form__filter-input-icon"}}
+{{#in-element this.modalHeaderAfterTitleElement}}
+  <p class="sidebar-categories-form__deselect">
+    <DButton
+      @class="btn-flat sidebar-categories-form__deselect-all-btn"
+      @label="sidebar.categories_form_modal.subtitle.button_text"
+      @ariaLabel="sidebar.categories_form_modal.subtitle.button_text"
+      @action={{this.deselectAll}}
+    />
 
-      <Input
-        class="sidebar-categories-form__filter-input-field"
-        placeholder={{i18n "sidebar.categories_form.filter_placeholder"}}
-        @type="text"
-        @value={{this.filter}}
-        {{on "input" (action "onFilterInput" value="target.value")}}
-      />
-    </div>
+    {{i18n "sidebar.categories_form_modal.subtitle.text"}}
+  </p>
+{{/in-element}}
 
-    {{#if (gt this.filteredCategoriesGroupings.length 0)}}
-      {{#each this.filteredCategoriesGroupings as |categories|}}
-        <div
-          class="sidebar-categories-form__row"
-          style={{html-safe (border-color categories.0.color "left")}}
-        >
+<div class="sidebar-categories-form-modal">
+  <DModalBody
+    @title="sidebar.categories_form_modal.title"
+    @class="sidebar-categories-form__modal-body"
+  >
+    <form class="sidebar-categories-form">
+      <div class="sidebar-categories-form__filter">
+        {{d-icon "search" class="sidebar-categories-form__filter-input-icon"}}
 
-          {{#each categories as |category|}}
-            <div
-              class="sidebar-categories-form__category-row"
-              data-category-id={{category.id}}
-              data-category-level={{category.level}}
-            >
-              <label
-                class="sidebar-categories-form__category-label"
-                for={{concat "sidebar-categories-form__input--" category.id}}
-              >
-                <div class="sidebar-categories-form__category-badge">
-                  {{category-badge category}}
-                </div>
-
-                {{#unless category.parentCategory}}
-                  <div class="sidebar-categories-form__category-description">
-                    {{dir-span category.description_excerpt htmlSafe="true"}}
-                  </div>
-                {{/unless}}
-              </label>
-
-              <Input
-                id={{concat "sidebar-categories-form__input--" category.id}}
-                class="sidebar-categories-form__input"
-                @type="checkbox"
-                @checked={{includes
-                  this.selectedSidebarCategoryIds
-                  category.id
-                }}
-                {{on "click" (action "toggleCategory" category.id)}}
-              />
-            </div>
-          {{/each}}
-        </div>
-      {{/each}}
-    {{else}}
-      <div class="sidebar-categories-form__no-categories">
-        {{i18n "sidebar.categories_form.no_categories"}}
+        <Input
+          class="sidebar-categories-form__filter-input-field"
+          placeholder={{i18n
+            "sidebar.categories_form_modal.filter_placeholder"
+          }}
+          @type="text"
+          @value={{this.filter}}
+          {{on "input" (action "onFilterInput" value="target.value")}}
+        />
       </div>
-    {{/if}}
-  </form>
-</DModalBody>
 
-<div class="modal-footer">
-  <DButton
-    @class="btn-primary sidebar-categories-form__save-button"
-    @label="sidebar.categories_form.save"
-    @disabled={{this.saving}}
-    @action={{this.save}}
-  />
+      {{#if (gt this.filteredCategoriesGroupings.length 0)}}
+        {{#each this.filteredCategoriesGroupings as |categories|}}
+          <div
+            class="sidebar-categories-form__row"
+            style={{html-safe (border-color categories.0.color "left")}}
+          >
+
+            {{#each categories as |category|}}
+              <div
+                class="sidebar-categories-form__category-row"
+                data-category-id={{category.id}}
+                data-category-level={{category.level}}
+              >
+                <label
+                  class="sidebar-categories-form__category-label"
+                  for={{concat "sidebar-categories-form__input--" category.id}}
+                >
+                  <div class="sidebar-categories-form__category-badge">
+                    {{category-badge category}}
+                  </div>
+
+                  {{#unless category.parentCategory}}
+                    <div class="sidebar-categories-form__category-description">
+                      {{dir-span category.description_excerpt htmlSafe="true"}}
+                    </div>
+                  {{/unless}}
+                </label>
+
+                <Input
+                  id={{concat "sidebar-categories-form__input--" category.id}}
+                  class="sidebar-categories-form__input"
+                  @type="checkbox"
+                  @checked={{includes
+                    this.selectedSidebarCategoryIds
+                    category.id
+                  }}
+                  {{on "click" (action "toggleCategory" category.id)}}
+                />
+              </div>
+            {{/each}}
+          </div>
+        {{/each}}
+      {{else}}
+        <div class="sidebar-categories-form__no-categories">
+          {{i18n "sidebar.categories_form_modal.no_categories"}}
+        </div>
+      {{/if}}
+    </form>
+  </DModalBody>
+
+  <div class="modal-footer sidebar-categories-form__modal-footer">
+    <DButton
+      @class="btn-primary sidebar-categories-form__save-button"
+      @label="sidebar.categories_form_modal.save"
+      @disabled={{this.saving}}
+      @action={{this.save}}
+    />
+
+    {{#if (gt this.siteSettings.default_navigation_menu_categories.length 0)}}
+      <DButton
+        @icon="undo"
+        @class="btn-flat btn-text sidebar-categories-form__reset-to-defaults-btn"
+        @label="sidebar.categories_form_modal.reset_to_defaults"
+        @disabled={{this.saving}}
+        @action={{this.resetToDefaults}}
+      />
+    {{/if}}
+  </div>
 </div>
\ No newline at end of file
diff --git a/app/assets/javascripts/discourse/app/components/sidebar/categories-form-modal.js b/app/assets/javascripts/discourse/app/components/sidebar/categories-form-modal.js
index f0ccc8308ea..3d41dcc2054 100644
--- a/app/assets/javascripts/discourse/app/components/sidebar/categories-form-modal.js
+++ b/app/assets/javascripts/discourse/app/components/sidebar/categories-form-modal.js
@@ -8,8 +8,9 @@ import discourseDebounce from "discourse-common/lib/debounce";
 import { popupAjaxError } from "discourse/lib/ajax-error";
 
 export default class extends Component {
-  @service site;
   @service currentUser;
+  @service site;
+  @service siteSettings;
 
   @tracked filter = "";
 
@@ -85,6 +86,11 @@ export default class extends Component {
     this.filter = filter.toLowerCase();
   }
 
+  @action
+  deselectAll() {
+    this.selectedSidebarCategoryIds.clear();
+  }
+
   @action
   toggleCategory(categoryId) {
     if (this.selectedSidebarCategoryIds.includes(categoryId)) {
@@ -94,6 +100,18 @@ export default class extends Component {
     }
   }
 
+  get modalHeaderAfterTitleElement() {
+    return document.getElementById("modal-header-after-title");
+  }
+
+  @action
+  resetToDefaults() {
+    this.selectedSidebarCategoryIds =
+      this.siteSettings.default_navigation_menu_categories
+        .split("|")
+        .map((id) => parseInt(id, 10));
+  }
+
   @action
   save() {
     this.saving = true;
diff --git a/app/assets/stylesheets/common/base/modal.scss b/app/assets/stylesheets/common/base/modal.scss
index 8b8f8fa4e44..b9fe680a575 100644
--- a/app/assets/stylesheets/common/base/modal.scss
+++ b/app/assets/stylesheets/common/base/modal.scss
@@ -134,7 +134,7 @@
   }
 
   &:not(.history-modal) {
-    .modal-body:not(.reorder-categories):not(.poll-ui-builder):not(.poll-breakdown):not(.sidebar-categories-form-modal) {
+    .modal-body:not(.reorder-categories):not(.poll-ui-builder):not(.poll-breakdown):not(.sidebar-categories-form__modal-body) {
       max-height: 80vh !important;
       @media screen and (max-height: 500px) {
         max-height: 65vh !important;
diff --git a/app/assets/stylesheets/common/components/sidebar-categories-form.scss b/app/assets/stylesheets/common/components/sidebar-categories-form.scss
index c2b3c7602bb..3f5aa358c7d 100644
--- a/app/assets/stylesheets/common/components/sidebar-categories-form.scss
+++ b/app/assets/stylesheets/common/components/sidebar-categories-form.scss
@@ -4,13 +4,43 @@
   }
 }
 
+.sidebar-categories-form__modal-footer.modal-footer {
+  .sidebar-categories-form__reset-to-defaults-btn {
+    margin-left: auto;
+    margin-right: 0em;
+
+    .d-icon {
+      font-size: var(--font-down-1);
+      color: var(--tertiary);
+    }
+
+    &:focus,
+    &:active {
+      background: none;
+    }
+  }
+}
+
+.sidebar-categories-form__deselect {
+  margin: 0;
+
+  .btn-flat.sidebar-categories-form__deselect-all-btn {
+    margin-left: auto;
+    padding: 0;
+
+    &:focus,
+    &:active {
+      background: none;
+    }
+  }
+}
+
 .sidebar-categories-form {
   .sidebar-categories-form__filter {
     display: flex;
     flex-direction: row;
     margin-right: auto;
     width: 100%;
-    margin-bottom: 1em;
     position: relative;
   }
 
diff --git a/config/locales/client.en.yml b/config/locales/client.en.yml
index aa9f92abd10..40dbc4cab12 100644
--- a/config/locales/client.en.yml
+++ b/config/locales/client.en.yml
@@ -4389,11 +4389,15 @@ en:
       more: "More"
       all_categories: "All categories"
       all_tags: "All tags"
-      categories_form:
+      categories_form_modal:
         save: "Save"
         title: "Edit categories navigation"
+        subtitle:
+          button_text: "Deselect all"
+          text: "and we'll automatically show this site's most popular categories"
         filter_placeholder: "Filter categories"
         no_categories: "There are no categories matching the given term."
+        reset_to_defaults: "Reset to defaults"
 
       sections:
         custom:
diff --git a/spec/system/editing_sidebar_categories_navigation_spec.rb b/spec/system/editing_sidebar_categories_navigation_spec.rb
index 4b527a28566..e83d7c72d0e 100644
--- a/spec/system/editing_sidebar_categories_navigation_spec.rb
+++ b/spec/system/editing_sidebar_categories_navigation_spec.rb
@@ -22,7 +22,6 @@ RSpec.describe "Editing sidebar categories navigation", type: :system do
 
   before do
     SiteSetting.new_edit_sidebar_categories_tags_interface_groups = group.name
-    SiteSetting.default_navigation_menu_categories = "#{category.id}|#{category2.id}"
     sign_in(user)
   end
 
@@ -33,11 +32,12 @@ RSpec.describe "Editing sidebar categories navigation", type: :system do
 
     modal = sidebar.click_edit_categories_button
 
-    expect(modal).to have_right_title(I18n.t("js.sidebar.categories_form.title"))
+    expect(modal).to have_right_title(I18n.t("js.sidebar.categories_form_modal.title"))
     expect(modal).to have_parent_category_color(category)
     expect(modal).to have_category_description_excerpt(category)
     expect(modal).to have_parent_category_color(category2)
     expect(modal).to have_category_description_excerpt(category2)
+    expect(modal).to have_no_reset_to_defaults_button
 
     expect(modal).to have_categories(
       [category, category_subcategory, category_subcategory2, category2, category2_subcategory],
@@ -71,6 +71,47 @@ RSpec.describe "Editing sidebar categories navigation", type: :system do
     expect(sidebar).to have_no_section_link(category2.name)
   end
 
+  it "allows a user to deselect all categories in the modal" do
+    Fabricate(:category_sidebar_section_link, linkable: category, user: user)
+    Fabricate(:category_sidebar_section_link, linkable: category_subcategory2, user: user)
+
+    visit "/latest"
+
+    expect(sidebar).to have_categories_section
+
+    modal = sidebar.click_edit_categories_button
+    modal.deselect_all.save
+
+    expect(sidebar).to have_section_link(category.name)
+    expect(sidebar).to have_no_section_link(category_subcategory2.name)
+    expect(sidebar).to have_section_link(category2.name)
+    expect(sidebar).to have_section_link("Uncategorized")
+  end
+
+  it "allows a user to reset to the default navigation menu categories site setting" do
+    Fabricate(:category_sidebar_section_link, linkable: category, user: user)
+    Fabricate(:category_sidebar_section_link, linkable: category2, user: user)
+
+    SiteSetting.default_navigation_menu_categories =
+      "#{category_subcategory2.id}|#{category2_subcategory.id}"
+
+    visit "/latest"
+
+    expect(sidebar).to have_categories_section
+    expect(sidebar).to have_section_link(category.name)
+    expect(sidebar).to have_section_link(category2.name)
+
+    modal = sidebar.click_edit_categories_button
+    modal.click_reset_to_defaults_button.save
+
+    expect(modal).to be_closed
+
+    expect(sidebar).to have_no_section_link(category.name)
+    expect(sidebar).to have_no_section_link(category2.name)
+    expect(sidebar).to have_section_link(category_subcategory2.name)
+    expect(sidebar).to have_section_link(category2_subcategory.name)
+  end
+
   it "allows a user to filter the categories in the modal by the category's name" do
     visit "/latest"
 
@@ -127,7 +168,7 @@ RSpec.describe "Editing sidebar categories navigation", type: :system do
 
       modal = sidebar.click_edit_categories_button
 
-      expect(modal).to have_right_title(I18n.t("js.sidebar.categories_form.title"))
+      expect(modal).to have_right_title(I18n.t("js.sidebar.categories_form_modal.title"))
 
       modal
         .toggle_category_checkbox(category_subcategory_subcategory)
diff --git a/spec/system/page_objects/modals/sidebar_edit_categories.rb b/spec/system/page_objects/modals/sidebar_edit_categories.rb
index 686a6e42559..bc8a3eba38f 100644
--- a/spec/system/page_objects/modals/sidebar_edit_categories.rb
+++ b/spec/system/page_objects/modals/sidebar_edit_categories.rb
@@ -29,7 +29,7 @@ module PageObjects
         has_no_css?(".sidebar-categories-form-modal .sidebar-categories-form__category-row") &&
           has_css?(
             ".sidebar-categories-form-modal .sidebar-categories-form__no-categories",
-            text: I18n.t("js.sidebar.categories_form.no_categories"),
+            text: I18n.t("js.sidebar.categories_form_modal.no_categories"),
           )
       end
 
@@ -65,6 +65,20 @@ module PageObjects
 
         self
       end
+
+      def deselect_all
+        click_button(I18n.t("js.sidebar.categories_form_modal.subtitle.button_text"))
+        self
+      end
+
+      def click_reset_to_defaults_button
+        click_button(I18n.t("js.sidebar.categories_form_modal.reset_to_defaults"))
+        self
+      end
+
+      def has_no_reset_to_defaults_button?
+        has_no_button?(I18n.t("js.sidebar.categories_form_modal.reset_to_defaults"))
+      end
     end
   end
 end