diff --git a/packages/docusaurus-plugin-content-docs/src/__tests__/__fixtures__/sidebars/sidebars-category.js b/packages/docusaurus-plugin-content-docs/src/__tests__/__fixtures__/sidebars/sidebars-category.js
index 402803c0c4..975f1203fe 100644
--- a/packages/docusaurus-plugin-content-docs/src/__tests__/__fixtures__/sidebars/sidebars-category.js
+++ b/packages/docusaurus-plugin-content-docs/src/__tests__/__fixtures__/sidebars/sidebars-category.js
@@ -9,25 +9,30 @@ module.exports = {
   docs: [
     {
       type: 'category',
+      collapsed: true,
       label: 'level 1',
       items: [
         'a',
         {
           type: 'category',
+          collapsed: true,
           label: 'level 2',
           items: [
             {
               type: 'category',
+              collapsed: true,
               label: 'level 3',
               items: [
                 'c',
                 {
                   type: 'category',
+                  collapsed: true,
                   label: 'level 4',
                   items: [
                     'd',
                     {
                       type: 'category',
+                      collapsed: true,
                       label: 'deeper more more',
                       items: ['e'],
                     },
diff --git a/packages/docusaurus-plugin-content-docs/src/__tests__/__fixtures__/sidebars/sidebars-collapsed-first-level.json b/packages/docusaurus-plugin-content-docs/src/__tests__/__fixtures__/sidebars/sidebars-collapsed-first-level.json
new file mode 100644
index 0000000000..1251a7d454
--- /dev/null
+++ b/packages/docusaurus-plugin-content-docs/src/__tests__/__fixtures__/sidebars/sidebars-collapsed-first-level.json
@@ -0,0 +1,20 @@
+{
+    "docs": [
+        {
+            "type": "category",
+            "label": "Introduction",
+            "items": [
+                "doc1"
+            ],
+            "collapsed": false
+        },
+        {
+            "type": "category",
+            "label": "Powering MDX",
+            "items": [
+                "doc2"
+            ],
+            "collapsed": false
+        }
+    ]
+}
\ No newline at end of file
diff --git a/packages/docusaurus-plugin-content-docs/src/__tests__/__fixtures__/sidebars/sidebars-collapsed.json b/packages/docusaurus-plugin-content-docs/src/__tests__/__fixtures__/sidebars/sidebars-collapsed.json
new file mode 100644
index 0000000000..2199c5f557
--- /dev/null
+++ b/packages/docusaurus-plugin-content-docs/src/__tests__/__fixtures__/sidebars/sidebars-collapsed.json
@@ -0,0 +1,21 @@
+{
+    "docs": {
+      "Test": [
+        {
+          "type": "category",
+          "label": "Introduction",
+          "items": ["doc1"],
+          "collapsed": false
+        }
+      ],
+      "Reference": [
+        {
+          "type": "category",
+          "label": "Powering MDX",
+          "items": ["doc2"],
+          "collapsed": false
+        }
+      ]
+    }
+  }
+  
\ No newline at end of file
diff --git a/packages/docusaurus-plugin-content-docs/src/__tests__/__snapshots__/index.test.ts.snap b/packages/docusaurus-plugin-content-docs/src/__tests__/__snapshots__/index.test.ts.snap
index 11d22b0c99..dd85d4c264 100644
--- a/packages/docusaurus-plugin-content-docs/src/__tests__/__snapshots__/index.test.ts.snap
+++ b/packages/docusaurus-plugin-content-docs/src/__tests__/__snapshots__/index.test.ts.snap
@@ -4,6 +4,7 @@ exports[`simple website content 1`] = `
 Object {
   "docs": Array [
     Object {
+      "collapsed": true,
       "items": Array [
         Object {
           "items": Array [
@@ -36,6 +37,7 @@ Object {
       "type": "category",
     },
     Object {
+      "collapsed": true,
       "items": Array [
         Object {
           "href": "/docs/hello",
@@ -200,6 +202,7 @@ exports[`versioned website content: all sidebars 1`] = `
 Object {
   "docs": Array [
     Object {
+      "collapsed": true,
       "items": Array [
         Object {
           "href": "/docs/next/foo/bar",
@@ -211,6 +214,7 @@ Object {
       "type": "category",
     },
     Object {
+      "collapsed": true,
       "items": Array [
         Object {
           "href": "/docs/next/hello",
@@ -224,6 +228,7 @@ Object {
   ],
   "version-1.0.0/docs": Array [
     Object {
+      "collapsed": true,
       "items": Array [
         Object {
           "href": "/docs/1.0.0/foo/bar",
@@ -240,6 +245,7 @@ Object {
       "type": "category",
     },
     Object {
+      "collapsed": true,
       "items": Array [
         Object {
           "href": "/docs/1.0.0/hello",
@@ -253,6 +259,7 @@ Object {
   ],
   "version-1.0.1/docs": Array [
     Object {
+      "collapsed": true,
       "items": Array [
         Object {
           "href": "/docs/foo/bar",
@@ -264,6 +271,7 @@ Object {
       "type": "category",
     },
     Object {
+      "collapsed": true,
       "items": Array [
         Object {
           "href": "/docs/hello",
@@ -283,6 +291,7 @@ Object {
   "docsSidebars": Object {
     "version-1.0.0/docs": Array [
       Object {
+        "collapsed": true,
         "items": Array [
           Object {
             "href": "/docs/1.0.0/foo/bar",
@@ -299,6 +308,7 @@ Object {
         "type": "category",
       },
       Object {
+        "collapsed": true,
         "items": Array [
           Object {
             "href": "/docs/1.0.0/hello",
@@ -325,6 +335,7 @@ Object {
   "docsSidebars": Object {
     "version-1.0.1/docs": Array [
       Object {
+        "collapsed": true,
         "items": Array [
           Object {
             "href": "/docs/foo/bar",
@@ -336,6 +347,7 @@ Object {
         "type": "category",
       },
       Object {
+        "collapsed": true,
         "items": Array [
           Object {
             "href": "/docs/hello",
@@ -361,6 +373,7 @@ Object {
   "docsSidebars": Object {
     "docs": Array [
       Object {
+        "collapsed": true,
         "items": Array [
           Object {
             "href": "/docs/next/foo/bar",
@@ -372,6 +385,7 @@ Object {
         "type": "category",
       },
       Object {
+        "collapsed": true,
         "items": Array [
           Object {
             "href": "/docs/next/hello",
diff --git a/packages/docusaurus-plugin-content-docs/src/__tests__/__snapshots__/sidebars.test.ts.snap b/packages/docusaurus-plugin-content-docs/src/__tests__/__snapshots__/sidebars.test.ts.snap
index e0bc01bdc9..0aa670c44b 100644
--- a/packages/docusaurus-plugin-content-docs/src/__tests__/__snapshots__/sidebars.test.ts.snap
+++ b/packages/docusaurus-plugin-content-docs/src/__tests__/__snapshots__/sidebars.test.ts.snap
@@ -4,6 +4,7 @@ exports[`loadSidebars sidebars link 1`] = `
 Object {
   "docs": Array [
     Object {
+      "collapsed": true,
       "items": Array [
         Object {
           "href": "https://github.com",
@@ -18,30 +19,107 @@ Object {
 }
 `;
 
+exports[`loadSidebars sidebars with category.collapsed property 1`] = `
+Object {
+  "docs": Array [
+    Object {
+      "collapsed": true,
+      "items": Array [
+        Object {
+          "collapsed": false,
+          "items": Array [
+            Object {
+              "id": "doc1",
+              "type": "doc",
+            },
+          ],
+          "label": "Introduction",
+          "type": "category",
+        },
+      ],
+      "label": "Test",
+      "type": "category",
+    },
+    Object {
+      "collapsed": true,
+      "items": Array [
+        Object {
+          "collapsed": false,
+          "items": Array [
+            Object {
+              "id": "doc2",
+              "type": "doc",
+            },
+          ],
+          "label": "Powering MDX",
+          "type": "category",
+        },
+      ],
+      "label": "Reference",
+      "type": "category",
+    },
+  ],
+}
+`;
+
+exports[`loadSidebars sidebars with category.collapsed property at first level 1`] = `
+Object {
+  "docs": Array [
+    Object {
+      "collapsed": false,
+      "items": Array [
+        Object {
+          "id": "doc1",
+          "type": "doc",
+        },
+      ],
+      "label": "Introduction",
+      "type": "category",
+    },
+    Object {
+      "collapsed": false,
+      "items": Array [
+        Object {
+          "id": "doc2",
+          "type": "doc",
+        },
+      ],
+      "label": "Powering MDX",
+      "type": "category",
+    },
+  ],
+}
+`;
+
 exports[`loadSidebars sidebars with deep level of category 1`] = `
 Object {
   "docs": Array [
     Object {
+      "collapsed": true,
       "items": Array [
         Object {
           "id": "a",
           "type": "doc",
         },
         Object {
+          "collapsed": true,
           "items": Array [
             Object {
+              "collapsed": true,
               "items": Array [
                 Object {
                   "id": "c",
                   "type": "doc",
                 },
                 Object {
+                  "collapsed": true,
                   "items": Array [
                     Object {
                       "id": "d",
                       "type": "doc",
                     },
                     Object {
+                      "collapsed": true,
                       "items": Array [
                         Object {
                           "id": "e",
@@ -100,6 +178,7 @@ exports[`loadSidebars sidebars with known sidebar item type 1`] = `
 Object {
   "docs": Array [
     Object {
+      "collapsed": true,
       "items": Array [
         Object {
           "id": "foo/bar",
@@ -123,6 +202,7 @@ Object {
       "type": "category",
     },
     Object {
+      "collapsed": true,
       "items": Array [
         Object {
           "id": "hello",
diff --git a/packages/docusaurus-plugin-content-docs/src/__tests__/__snapshots__/version.test.ts.snap b/packages/docusaurus-plugin-content-docs/src/__tests__/__snapshots__/version.test.ts.snap
index 47ffaef77f..26c10f3c0a 100644
--- a/packages/docusaurus-plugin-content-docs/src/__tests__/__snapshots__/version.test.ts.snap
+++ b/packages/docusaurus-plugin-content-docs/src/__tests__/__snapshots__/version.test.ts.snap
@@ -4,6 +4,7 @@ exports[`docsVersion first time versioning 1`] = `
 Object {
   "version-1.0.0/docs": Array [
     Object {
+      "collapsed": true,
       "items": Array [
         Object {
           "items": Array [
@@ -33,6 +34,7 @@ Object {
       "type": "category",
     },
     Object {
+      "collapsed": true,
       "items": Array [
         Object {
           "id": "version-1.0.0/hello",
@@ -50,6 +52,7 @@ exports[`docsVersion not the first time versioning 1`] = `
 Object {
   "version-2.0.0/docs": Array [
     Object {
+      "collapsed": true,
       "items": Array [
         Object {
           "id": "version-2.0.0/foo/bar",
@@ -60,6 +63,7 @@ Object {
       "type": "category",
     },
     Object {
+      "collapsed": true,
       "items": Array [
         Object {
           "id": "version-2.0.0/hello",
diff --git a/packages/docusaurus-plugin-content-docs/src/__tests__/sidebars.test.ts b/packages/docusaurus-plugin-content-docs/src/__tests__/sidebars.test.ts
index 49a788dfd9..11d882b22a 100644
--- a/packages/docusaurus-plugin-content-docs/src/__tests__/sidebars.test.ts
+++ b/packages/docusaurus-plugin-content-docs/src/__tests__/sidebars.test.ts
@@ -126,4 +126,19 @@ describe('loadSidebars', () => {
     const result = loadSidebars(null);
     expect(result).toEqual({});
   });
+
+  test('sidebars with category.collapsed property', async () => {
+    const sidebarPath = path.join(fixtureDir, 'sidebars-collapsed.json');
+    const result = loadSidebars([sidebarPath]);
+    expect(result).toMatchSnapshot();
+  });
+
+  test('sidebars with category.collapsed property at first level', async () => {
+    const sidebarPath = path.join(
+      fixtureDir,
+      'sidebars-collapsed-first-level.json',
+    );
+    const result = loadSidebars([sidebarPath]);
+    expect(result).toMatchSnapshot();
+  });
 });
diff --git a/packages/docusaurus-plugin-content-docs/src/sidebars.ts b/packages/docusaurus-plugin-content-docs/src/sidebars.ts
index cfe1b36254..abe988984b 100644
--- a/packages/docusaurus-plugin-content-docs/src/sidebars.ts
+++ b/packages/docusaurus-plugin-content-docs/src/sidebars.ts
@@ -33,6 +33,7 @@ function normalizeCategoryShorthand(
 ): SidebarItemCategoryRaw[] {
   return Object.entries(sidebar).map(([label, items]) => ({
     type: 'category',
+    collapsed: true,
     label,
     items,
   }));
@@ -56,7 +57,7 @@ function assertItem(item: Object, keys: string[]): void {
 }
 
 function assertIsCategory(item: any): asserts item is SidebarItemCategoryRaw {
-  assertItem(item, ['items', 'label']);
+  assertItem(item, ['items', 'label', 'collapsed']);
   if (typeof item.label !== 'string') {
     throw new Error(
       `Error loading ${JSON.stringify(item)}. "label" must be a string.`,
@@ -67,6 +68,12 @@ function assertIsCategory(item: any): asserts item is SidebarItemCategoryRaw {
       `Error loading ${JSON.stringify(item)}. "items" must be an array.`,
     );
   }
+  // "collapsed" is an optional property
+  if (item.hasOwnProperty('collapsed') && typeof item.collapsed !== 'boolean') {
+    throw new Error(
+      `Error loading ${JSON.stringify(item)}. "collapsed" must be a boolean.`,
+    );
+  }
 }
 
 function assertIsDoc(item: any): asserts item is SidebarItemDoc {
diff --git a/packages/docusaurus-plugin-content-docs/src/types.ts b/packages/docusaurus-plugin-content-docs/src/types.ts
index 4929797c59..9516cec3f7 100644
--- a/packages/docusaurus-plugin-content-docs/src/types.ts
+++ b/packages/docusaurus-plugin-content-docs/src/types.ts
@@ -40,12 +40,14 @@ export interface SidebarItemCategory {
   type: 'category';
   label: string;
   items: SidebarItem[];
+  collapsed?: boolean;
 }
 
 export interface SidebarItemCategoryRaw {
   type: 'category';
   label: string;
   items: SidebarItemRaw[];
+  collapsed?: boolean;
 }
 
 export type SidebarItem =
@@ -81,6 +83,7 @@ export interface DocsSidebarItemCategory {
   type: 'category';
   label: string;
   items: DocsSidebarItem[];
+  collapsed?: boolean;
 }
 
 export type DocsSidebarItem = SidebarItemLink | DocsSidebarItemCategory;
diff --git a/packages/docusaurus-theme-classic/src/theme/DocSidebar/index.js b/packages/docusaurus-theme-classic/src/theme/DocSidebar/index.js
index c59c3611f4..29bdfa2b70 100644
--- a/packages/docusaurus-theme-classic/src/theme/DocSidebar/index.js
+++ b/packages/docusaurus-theme-classic/src/theme/DocSidebar/index.js
@@ -105,8 +105,11 @@ function mutateSidebarCollapsingState(item, path) {
         items
           .map((childItem) => mutateSidebarCollapsingState(childItem, path))
           .filter((val) => val).length > 0;
-      // eslint-disable-next-line no-param-reassign
-      item.collapsed = !anyChildItemsActive;
+      // only modify item.collapsed if there are child items active and the category collapsed is set to true
+      if (anyChildItemsActive && item.collapsed) {
+        // eslint-disable-next-line no-param-reassign
+        item.collapsed = !anyChildItemsActive;
+      }
       return anyChildItemsActive;
     }
 
diff --git a/website/docs/docs.md b/website/docs/docs.md
index d44c89ebed..b46a67309f 100644
--- a/website/docs/docs.md
+++ b/website/docs/docs.md
@@ -207,6 +207,7 @@ type SidebarItemCategory = {
   type: 'category';
   label: string; // Sidebar label text.
   items: SidebarItem[]; // Array of sidebar items.
+  collapsed: boolean; // Set the category to be collapsed or open by default
 };
 ```