diff --git a/CHANGELOG.md b/CHANGELOG.md
index 41bbfa52e..a7653652e 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -35,7 +35,8 @@
 - HedgeDoc instances can now be branded either with a '@ <custom string>' or '@ <custom logo>' after the HedgeDoc logo and text
 - Images will be loaded via proxy if an image proxy is configured in the backend
 - Asciinema videos may now be embedded by pasting the URL of one video into a single line
-- The Toolbar includes an EmojiPicker
+- The toolbar includes an EmojiPicker
+- Collapsable blocks can be added via a toolbar button or via autocompletion of "<details"
 - Added shortcodes for [fork-awesome icons](https://forkaweso.me/Fork-Awesome/icons/) (e.g. `:fa-picture-o:`)
 - The code button now adds code fences even if the user selected nothing beforehand
 - Code blocks with 'csv' as language render as tables.
diff --git a/cypress/integration/autocompletion.spec.ts b/cypress/integration/autocompletion.spec.ts
index 4d37239c2..b3f4d54f4 100644
--- a/cypress/integration/autocompletion.spec.ts
+++ b/cypress/integration/autocompletion.spec.ts
@@ -265,4 +265,34 @@ describe('Autocompletion', () => {
         .should('exist')
     })
   })
+
+  describe('collapsable blocks', () => {
+    it('via Enter', () => {
+      cy.get('.CodeMirror textarea')
+      .type('<d')
+      cy.get('.CodeMirror-hints')
+      .should('exist')
+      cy.get('.CodeMirror textarea')
+      .type('{enter}')
+      cy.get('.CodeMirror-hints')
+      .should('not.exist')
+      cy.get('.CodeMirror-activeline > .CodeMirror-line > span')
+      .should('have.text', '</details>') // after selecting the hint, the last line of the inserted suggestion is active
+      cy.get('.markdown-body > details')
+      .should('exist')
+    })
+    it('via doubleclick', () => {
+      cy.get('.CodeMirror textarea')
+      .type('<d')
+      cy.get('.CodeMirror-hints > li')
+      .first()
+      .dblclick()
+      cy.get('.CodeMirror-hints')
+      .should('not.exist')
+      cy.get('.CodeMirror-activeline > .CodeMirror-line > span')
+      .should('have.text', '</details>')
+      cy.get('.markdown-body > details')
+      .should('exist')
+    })
+  })
 })
diff --git a/cypress/integration/toolbar.spec.ts b/cypress/integration/toolbar.spec.ts
index 4ce5553cb..4cc62e835 100644
--- a/cypress/integration/toolbar.spec.ts
+++ b/cypress/integration/toolbar.spec.ts
@@ -261,6 +261,13 @@ describe('Toolbar', () => {
       .should('have.text', '----')
   })
 
+  it('collapsable block', () => {
+    cy.get('.fa-caret-square-o-down')
+    .click()
+    cy.get('.CodeMirror-code > div:nth-of-type(2) > .CodeMirror-line > span  span')
+    .should('have.text', '<details>')
+  })
+
   it('comment', () => {
     cy.get('.fa-comment')
       .click()
diff --git a/public/locales/en.json b/public/locales/en.json
index 9d2ee8363..46cb74edb 100644
--- a/public/locales/en.json
+++ b/public/locales/en.json
@@ -256,6 +256,7 @@
             "uploadImage": "Upload Image",
             "table": "Table",
             "line": "Horizontal line",
+            "collapsableBlock": "Collapsable block",
             "comment": "Comment",
             "preferences": "Editor settings",
             "emoji": "Open emoji picker"
diff --git a/src/components/editor/editor-pane/autocompletion/collapsable-block.ts b/src/components/editor/editor-pane/autocompletion/collapsable-block.ts
new file mode 100644
index 000000000..a2c45b4d1
--- /dev/null
+++ b/src/components/editor/editor-pane/autocompletion/collapsable-block.ts
@@ -0,0 +1,35 @@
+import { Editor, Hint, Hints, Pos } from 'codemirror'
+import { findWordAtCursor, Hinter } from './index'
+
+const allowedChars = /[<\w>]/
+const wordRegExp = /^(<d(?:e|et|eta|etai|etail|etails)?)$/
+
+const collapsableBlockHint = (editor: Editor): Promise< Hints| null > => {
+  return new Promise((resolve) => {
+    const searchTerm = findWordAtCursor(editor, allowedChars)
+    const searchResult = wordRegExp.exec(searchTerm.text)
+    if (searchResult === null) {
+      resolve(null)
+      return
+    }
+    const suggestions = ['<details>\n  <summary>Toggle label</summary>\n  Toggled content\n</details>']
+    const cursor = editor.getCursor()
+    if (!suggestions) {
+      resolve(null)
+    } else {
+      resolve({
+        list: suggestions.map((suggestion: string): Hint => ({
+          text: suggestion
+        })),
+        from: Pos(cursor.line, searchTerm.start),
+        to: Pos(cursor.line, searchTerm.end + 1)
+      })
+    }
+  })
+}
+
+export const CollapsableBlockHinter: Hinter = {
+  allowedChars,
+  wordRegExp,
+  hint: collapsableBlockHint
+}
diff --git a/src/components/editor/editor-pane/autocompletion/index.ts b/src/components/editor/editor-pane/autocompletion/index.ts
index f290a5255..609d0e340 100644
--- a/src/components/editor/editor-pane/autocompletion/index.ts
+++ b/src/components/editor/editor-pane/autocompletion/index.ts
@@ -1,5 +1,6 @@
 import { Editor, Hints } from 'codemirror'
 import { CodeBlockHinter } from './code-block'
+import { CollapsableBlockHinter } from './collapsable-block'
 import { ContainerHinter } from './container'
 import { EmojiHinter } from './emoji'
 import { HeaderHinter } from './header'
@@ -55,5 +56,6 @@ export const allHinters: Hinter[] = [
   HeaderHinter,
   ImageHinter,
   LinkAndExtraTagHinter,
-  PDFHinter
+  PDFHinter,
+  CollapsableBlockHinter
 ]
diff --git a/src/components/editor/editor-pane/tool-bar/tool-bar.tsx b/src/components/editor/editor-pane/tool-bar/tool-bar.tsx
index 880b6a4f0..87fcf88dd 100644
--- a/src/components/editor/editor-pane/tool-bar/tool-bar.tsx
+++ b/src/components/editor/editor-pane/tool-bar/tool-bar.tsx
@@ -8,6 +8,7 @@ import { EmojiPickerButton } from './emoji-picker/emoji-picker-button'
 import './tool-bar.scss'
 import {
   addCodeFences,
+  addCollapsableBlock,
   addComment,
   addHeaderLevel,
   addImage,
@@ -101,6 +102,9 @@ export const ToolBar: React.FC<ToolBarProps> = ({ editor }) => {
         <Button variant='light' onClick={() => addLine(editor)} title={t('editor.editorToolbar.line')}>
           <ForkAwesomeIcon icon="minus"/>
         </Button>
+        <Button variant='light' onClick={() => addCollapsableBlock(editor)} title={t('editor.editorToolbar.collapsableBlock')}>
+          <ForkAwesomeIcon icon="caret-square-o-down"/>
+        </Button>
         <Button variant='light' onClick={() => addComment(editor)} title={t('editor.editorToolbar.comment')}>
           <ForkAwesomeIcon icon="comment"/>
         </Button>
diff --git a/src/components/editor/editor-pane/tool-bar/utils/toolbarButtonUtils.test.ts b/src/components/editor/editor-pane/tool-bar/utils/toolbarButtonUtils.test.ts
index 245d7eacf..53c296b15 100644
--- a/src/components/editor/editor-pane/tool-bar/utils/toolbarButtonUtils.test.ts
+++ b/src/components/editor/editor-pane/tool-bar/utils/toolbarButtonUtils.test.ts
@@ -3,6 +3,7 @@ import { EmojiData } from 'emoji-mart'
 import { Mock } from 'ts-mockery'
 import {
   addCodeFences,
+  addCollapsableBlock,
   addComment,
   addEmoji,
   addHeaderLevel,
@@ -1499,6 +1500,93 @@ describe('test addLine', () => {
     addLine(editor)
   })
 })
+
+describe('test collapsable block', () => {
+  const { cursor, firstLine, multiline, multilineOffset } = buildRanges()
+  const textFirstLine = testContent.split('\n')[0]
+  it('just cursor', done => {
+    Mock.extend(editor).with({
+      listSelections: () => (
+        Mock.of<Range[]>([{
+          anchor: cursor.from,
+          head: cursor.to,
+          from: () => cursor.from,
+          to: () => cursor.to,
+          empty: () => true
+        }])
+      ),
+      getLine: (): string => (textFirstLine),
+      replaceRange: (replacement: string | string[]) => {
+        expect(replacement).toEqual(`${textFirstLine}\n<details>\n  <summary>Toggle label</summary>\n  Toggled content\n</details>`)
+        done()
+      }
+    })
+    addCollapsableBlock(editor)
+  })
+
+  it('1st line', done => {
+    Mock.extend(editor).with({
+      listSelections: () => (
+        Mock.of<Range[]>([{
+          anchor: firstLine.from,
+          head: firstLine.to,
+          from: () => firstLine.from,
+          to: () => firstLine.to,
+          empty: () => false
+        }])
+      ),
+      getLine: (): string => (textFirstLine),
+      replaceRange: (replacement: string | string[], from: CodeMirror.Position, to?: CodeMirror.Position) => {
+        expect(from).toEqual(firstLine.from)
+        expect(to).toEqual(firstLine.to)
+        expect(replacement).toEqual(`${textFirstLine}\n<details>\n  <summary>Toggle label</summary>\n  Toggled content\n</details>`)
+        done()
+      }
+    })
+    addCollapsableBlock(editor)
+  })
+
+  it('multiple lines', done => {
+    Mock.extend(editor).with({
+      listSelections: () => (
+        Mock.of<Range[]>([{
+          anchor: multiline.from,
+          head: multiline.to,
+          from: () => multiline.from,
+          to: () => multiline.to,
+          empty: () => false
+        }])
+      ),
+      getLine: (): string => '2nd line',
+      replaceRange: (replacement: string | string[]) => {
+        expect(replacement).toEqual('2nd line\n<details>\n  <summary>Toggle label</summary>\n  Toggled content\n</details>')
+        done()
+      }
+    })
+    addCollapsableBlock(editor)
+  })
+
+  it('multiple lines with offset', done => {
+    Mock.extend(editor).with({
+      listSelections: () => (
+        Mock.of<Range[]>([{
+          anchor: multilineOffset.from,
+          head: multilineOffset.to,
+          from: () => multilineOffset.from,
+          to: () => multilineOffset.to,
+          empty: () => false
+        }])
+      ),
+      getLine: (): string => '2nd line',
+      replaceRange: (replacement: string | string[]) => {
+        expect(replacement).toEqual('2nd line\n<details>\n  <summary>Toggle label</summary>\n  Toggled content\n</details>')
+        done()
+      }
+    })
+    addCollapsableBlock(editor)
+  })
+})
+
 describe('test addComment', () => {
   const { cursor, firstLine, multiline, multilineOffset } = buildRanges()
   const textFirstLine = testContent.split('\n')[0]
diff --git a/src/components/editor/editor-pane/tool-bar/utils/toolbarButtonUtils.ts b/src/components/editor/editor-pane/tool-bar/utils/toolbarButtonUtils.ts
index ed700aa8e..cfffe1f77 100644
--- a/src/components/editor/editor-pane/tool-bar/utils/toolbarButtonUtils.ts
+++ b/src/components/editor/editor-pane/tool-bar/utils/toolbarButtonUtils.ts
@@ -21,6 +21,7 @@ export const addTaskList = (editor: Editor): void => createList(editor, () => '-
 export const addImage = (editor: Editor): void => addLink(editor, '!')
 
 export const addLine = (editor: Editor): void => changeLines(editor, line => `${line}\n----`)
+export const addCollapsableBlock = (editor: Editor): void => changeLines(editor, line => `${line}\n<details>\n  <summary>Toggle label</summary>\n  Toggled content\n</details>`)
 export const addComment = (editor: Editor): void => changeLines(editor, line => `${line}\n> []`)
 export const addTable = (editor: Editor): void => changeLines(editor, line => `${line}\n| # 1  | # 2  | # 3  |\n| ---- | ---- | ---- |\n| Text | Text | Text |`)