diff --git a/packages/docusaurus-mdx-loader/src/remark/admonitions/__tests__/__fixtures__/nesting.md b/packages/docusaurus-mdx-loader/src/remark/admonitions/__tests__/__fixtures__/nesting.md
new file mode 100644
index 0000000000..04cb34755c
--- /dev/null
+++ b/packages/docusaurus-mdx-loader/src/remark/admonitions/__tests__/__fixtures__/nesting.md
@@ -0,0 +1,10 @@
+Test nested Admonitions
+
+::::info **Weather**
+On nice days, you can enjoy skiing in the mountains.
+
+:::danger *Storms*
+Take care of snowstorms...
+:::
+
+::::
\ No newline at end of file
diff --git a/packages/docusaurus-mdx-loader/src/remark/admonitions/__tests__/__snapshots__/index.test.ts.snap b/packages/docusaurus-mdx-loader/src/remark/admonitions/__tests__/__snapshots__/index.test.ts.snap
index 227eb28b33..d02da45a66 100644
--- a/packages/docusaurus-mdx-loader/src/remark/admonitions/__tests__/__snapshots__/index.test.ts.snap
+++ b/packages/docusaurus-mdx-loader/src/remark/admonitions/__tests__/__snapshots__/index.test.ts.snap
@@ -42,3 +42,8 @@ exports[`admonitions remark plugin interpolation 1`] = `
 "<p>Test admonition with interpolated title/body</p>
 <admonition type="tip"><mdxAdmonitionTitle>My <code>interpolated</code> <strong>title</strong> &#x3C;button style={{color: "red"}} onClick={() => alert("click")}>test</mdxAdmonitionTitle><p><code>body</code> <strong>interpolated</strong> content</p></admonition>"
 `;
+
+exports[`admonitions remark plugin nesting 1`] = `
+"<p>Test nested Admonitions</p>
+<admonition type="info"><mdxAdmonitionTitle><strong>Weather</strong></mdxAdmonitionTitle><p>On nice days, you can enjoy skiing in the mountains.</p><admonition type="danger"><mdxAdmonitionTitle><em>Storms</em></mdxAdmonitionTitle><p>Take care of snowstorms...</p></admonition></admonition>"
+`;
diff --git a/packages/docusaurus-mdx-loader/src/remark/admonitions/__tests__/index.test.ts b/packages/docusaurus-mdx-loader/src/remark/admonitions/__tests__/index.test.ts
index 3794562bb1..ee59edf894 100644
--- a/packages/docusaurus-mdx-loader/src/remark/admonitions/__tests__/index.test.ts
+++ b/packages/docusaurus-mdx-loader/src/remark/admonitions/__tests__/index.test.ts
@@ -50,4 +50,9 @@ describe('admonitions remark plugin', () => {
     const result = await processFixture('interpolation');
     expect(result).toMatchSnapshot();
   });
+
+  it('nesting', async () => {
+    const result = await processFixture('nesting');
+    expect(result).toMatchSnapshot();
+  });
 });
diff --git a/packages/docusaurus-mdx-loader/src/remark/admonitions/index.ts b/packages/docusaurus-mdx-loader/src/remark/admonitions/index.ts
index d6393b8c45..d7efad2a81 100644
--- a/packages/docusaurus-mdx-loader/src/remark/admonitions/index.ts
+++ b/packages/docusaurus-mdx-loader/src/remark/admonitions/index.ts
@@ -52,9 +52,20 @@ const plugin: Plugin = function plugin(
   const options = normalizeOptions(optionsInput);
 
   const keywords = Object.values(options.keywords).map(escapeRegExp).join('|');
+  const nestingChar = escapeRegExp(options.tag.slice(0, 1));
   const tag = escapeRegExp(options.tag);
-  const regex = new RegExp(`${tag}(${keywords})(?: *(.*))?\n`);
-  const escapeTag = new RegExp(escapeRegExp(`\\${options.tag}`), 'g');
+
+  // resolve th nesting level of an opening tag
+  // ::: -> 0, :::: -> 1, ::::: -> 2 ...
+  const nestingLevelRegex = new RegExp(
+    `^${tag}(?<nestingLevel>${nestingChar}*)`,
+  );
+
+  const regex = new RegExp(`${tag}${nestingChar}*(${keywords})(?: *(.*))?\n`);
+  const escapeTag = new RegExp(
+    escapeRegExp(`\\${options.tag}${options.tag.slice(0, 1)}*`),
+    'g',
+  );
 
   // The tokenizer is called on blocks to determine if there is an admonition
   // present and create tags for it
@@ -77,6 +88,11 @@ const plugin: Plugin = function plugin(
     ];
     const food = [];
     const content = [];
+    // get the nesting level of the opening tag
+    const openingLevel =
+      nestingLevelRegex.exec(opening)!.groups!.nestingLevel!.length;
+    // used as a stack to keep track of nested admonitions
+    const nestingLevels: number[] = [openingLevel];
 
     let newValue = value;
     // consume lines until a closing tag
@@ -88,12 +104,32 @@ const plugin: Plugin = function plugin(
         next !== -1 ? newValue.slice(idx + 1, next) : newValue.slice(idx + 1);
       food.push(line);
       newValue = newValue.slice(idx + 1);
-      // the closing tag is NOT part of the content
-      if (line.startsWith(options.tag)) {
-        break;
+      const nesting = nestingLevelRegex.exec(line);
+      idx = newValue.indexOf(NEWLINE);
+      if (!nesting) {
+        content.push(line);
+        continue;
+      }
+      const tagLevel = nesting.groups!.nestingLevel!.length;
+      // first level
+      if (nestingLevels.length === 0) {
+        nestingLevels.push(tagLevel);
+        content.push(line);
+        continue;
+      }
+      const currentLevel = nestingLevels[nestingLevels.length - 1]!;
+      if (tagLevel < currentLevel) {
+        // entering a nested admonition block
+        nestingLevels.push(tagLevel);
+      } else if (tagLevel === currentLevel) {
+        // closing a nested admonition block
+        nestingLevels.pop();
+        // the closing tag is NOT part of the content
+        if (nestingLevels.length === 0) {
+          break;
+        }
       }
       content.push(line);
-      idx = newValue.indexOf(NEWLINE);
     }
 
     // consume the processed tag and replace escape sequences
diff --git a/website/_dogfooding/_pages tests/markdownPageTests.md b/website/_dogfooding/_pages tests/markdownPageTests.md
index 323c741ee3..ce16704134 100644
--- a/website/_dogfooding/_pages tests/markdownPageTests.md	
+++ b/website/_dogfooding/_pages tests/markdownPageTests.md	
@@ -239,3 +239,31 @@ Can be arbitrarily nested:
 Admonition body
 
 :::
+
+:::important
+
+Admonition alias `:::important` should have Important title
+
+:::
+
+:::::note title
+
+Some **content** with _Markdown_ `syntax`.
+
+::::note nested Title
+
+:::tip very nested Title
+
+Some **content** with _Markdown_ `syntax`.
+
+:::
+
+Some **content** with _Markdown_ `syntax`.
+
+::::
+
+hey
+
+:::::
+
+after admonition
diff --git a/website/docs/guides/markdown-features/markdown-features-admonitions.mdx b/website/docs/guides/markdown-features/markdown-features-admonitions.mdx
index 719dd371c9..bf95ccbf70 100644
--- a/website/docs/guides/markdown-features/markdown-features-admonitions.mdx
+++ b/website/docs/guides/markdown-features/markdown-features-admonitions.mdx
@@ -11,7 +11,7 @@ import Tabs from '@theme/Tabs';
 import TabItem from '@theme/TabItem';
 import Admonition from '@theme/Admonition';
 
-In addition to the basic Markdown syntax, we use [remark-admonitions](https://github.com/elviswolcott/remark-admonitions) alongside MDX to add support for admonitions. Admonitions are wrapped by a set of 3 colons.
+In addition to the basic Markdown syntax, we have a special admonitions syntax by wrapping text with a set of 3 colons, followed by a label denoting its type.
 
 Example:
 
@@ -107,7 +107,7 @@ Hello world
 
 ## Specifying title {#specifying-title}
 
-You may also specify an optional title
+You may also specify an optional title.
 
 ```md
 :::note Your Title
@@ -204,3 +204,128 @@ The types that are accepted are the same as above: `note`, `tip`, `danger`, `inf
   </Admonition>
 </BrowserWindow>
 ```
+
+## Customizing admonitions {#customizing-admonitions}
+
+There are two kinds of customizations possible with admonitions: **parsing** and **rendering**.
+
+### Customizing rendering behavior {#customizing-rendering-behavior}
+
+You can customize how each individual admonition type is rendered through [swizzling](../../swizzling.md). You can often achieve your goal through a simple wrapper. For example, in the follow example, we swap out the icon for `info` admonitions only.
+
+```jsx title="src/theme/Admonition.js"
+import React from 'react';
+import Admonition from '@theme-original/Admonition';
+import MyCustomNoteIcon from '@site/static/img/info.svg';
+
+export default function AdmonitionWrapper(props) {
+  if (props.type !== 'info') {
+    return <Admonition title="My Custom Admonition Title" {...props} />;
+  }
+  return <Admonition icon={<MyCustomNoteIcon />} {...props} />;
+}
+```
+
+### Customizing parsing behavior {#customizing-parsing-behavior}
+
+Admonitions are implemented with a [Remark plugin](./markdown-features-plugins.mdx). The plugin is designed to be configurable. To customize the Remark plugin for a specific content plugin (docs, blog, pages), pass the options through the `admonitions` key.
+
+```js title="docusaurus.config.js"
+module.exports = {
+  presets: [
+    [
+      '@docusaurus/preset-classic',
+      {
+        docs: {
+          admonitions: {
+            tag: ':::',
+            keywords: ['note', 'tip', 'info', 'caution', 'danger'],
+            extendDefaults: true,
+          },
+        },
+      },
+    ],
+  ],
+};
+```
+
+The plugin accepts the following options:
+
+- `tag`: The tag that encloses the admonition. Defaults to `:::`.
+- `keywords`: An array of keywords that can be used as the type for the admonition.
+- `extendDefaults`: Should the provided options (such as `keywords`) be merged into the existing defaults. Defaults to `false`.
+
+The `keyword` will be passed as the `type` prop of the `Admonition` component.
+
+### Custom admonition type components {#custom-admonition-type-components}
+
+By default, the theme doesn't know what do to with custom admonition keywords such as `:::my-custom-admonition`. It is your responsibility to map each admonition keyword to a React component so that the theme knows how to render them.
+
+If you registered a new admonition type `my-custom-admonition` via the following config:
+
+```js title="docusaurus.config.js"
+module.exports = {
+  // ...
+  presets: [
+    [
+      'classic',
+      {
+        // ...
+        docs: {
+          admonitions: {
+            tag: ':::',
+            keywords: ['my-custom-admonition'],
+            extendDefaults: true,
+          },
+        },
+      },
+    ],
+  ],
+};
+```
+
+You can provide the corresponding React component for `:::my-custom-admonition` by creating the following file (unfortunately, since it's not a React component file, it's not swizzlable):
+
+```js title="src/theme/Admonition/Types.js"
+import React from 'react';
+import DefaultAdmonitionTypes from '@theme-original/Admonition/Types';
+
+function MyCustomAdmonition(props) {
+  return (
+    <div style={{border: 'solid red', padding: 10}}>
+      <h5 style={{color: 'blue', fontSize: 30}}>{props.title}</h5>
+      <div>{props.children}</div>
+    </div>
+  );
+}
+
+const AdmonitionTypes = {
+  ...DefaultAdmonitionTypes,
+
+  // Add all your custom admonition types here...
+  // You can also override the default ones if you want
+  'my-custom-admonition': MyCustomAdmonition,
+};
+
+export default AdmonitionTypes;
+```
+
+Now you can use your new admonition keyword in a Markdown file, and it will be parsed and rendered with your custom logic:
+
+```md
+:::my-custom-admonition Custom Admonition
+
+It works!
+
+:::
+```
+
+<BrowserWindow>
+
+:::my-custom-admonition Custom Admonition
+
+It works!
+
+:::
+
+</BrowserWindow>