diff --git a/nbconvert/exporters/html.py b/nbconvert/exporters/html.py
index 03d1462df..30c10b7f0 100644
--- a/nbconvert/exporters/html.py
+++ b/nbconvert/exporters/html.py
@@ -121,6 +121,15 @@ class HTMLExporter(TemplateExporter):
         """,
     ).tag(config=True)
 
+    mermaid_js_url = Unicode(
+        "https://cdnjs.cloudflare.com/ajax/libs/mermaid/10.2.3/mermaid.esm.min.mjs",
+        help="""
+        URL to load MermaidJS from.
+
+        Defaults to loading from cdnjs.
+        """,
+    )
+
     jquery_url = Unicode(
         "https://cdnjs.cloudflare.com/ajax/libs/jquery/2.0.3/jquery.min.js",
         help="""
@@ -303,6 +312,7 @@ def resources_include_url(name):
         resources["include_url"] = resources_include_url
         resources["require_js_url"] = self.require_js_url
         resources["mathjax_url"] = self.mathjax_url
+        resources["mermaid_js_url"] = self.mermaid_js_url
         resources["jquery_url"] = self.jquery_url
         resources["jupyter_widgets_base_url"] = self.jupyter_widgets_base_url
         resources["widget_renderer_url"] = self.widget_renderer_url
diff --git a/nbconvert/filters/markdown_mistune.py b/nbconvert/filters/markdown_mistune.py
index d7501b659..a7a9f05ed 100644
--- a/nbconvert/filters/markdown_mistune.py
+++ b/nbconvert/filters/markdown_mistune.py
@@ -176,6 +176,10 @@ def block_code(self, code, info=None):
         """Handle block code."""
         lang = ""
         lexer = None
+
+        if info and info.startswith("mermaid"):
+            return self.block_mermaidjs(code)
+
         if info:
             try:
                 lang = info.strip().split(None, 1)[0]
@@ -190,6 +194,14 @@ def block_code(self, code, info=None):
         formatter = HtmlFormatter()
         return highlight(code, lexer, formatter)
 
+    def block_mermaidjs(self, code, info=None):
+        """Handle mermaid syntax."""
+        return (
+            """<div class="jp-Mermaid"><pre class="mermaid">\n"""
+            f"""{code.strip()}"""
+            """\n</pre></div>"""
+        )
+
     def block_html(self, html):
         """Handle block html."""
         if self.embed_images:
diff --git a/nbconvert/filters/tests/test_markdown.py b/nbconvert/filters/tests/test_markdown.py
index a66432829..c271969eb 100644
--- a/nbconvert/filters/tests/test_markdown.py
+++ b/nbconvert/filters/tests/test_markdown.py
@@ -247,6 +247,19 @@ def test_markdown2rst(self):
                 tokens[index],
             )
 
+    def test_mermaid_markdown(self):
+        code = """flowchart LR
+            chicken --> egg --> chicken"""
+        case = f"""```mermaid\n  {code}\n```"""
+
+        output_check = (
+            """<div class="jp-Mermaid"><pre class="mermaid">\n"""
+            f"""{code.strip()}"""
+            """\n</pre></div>"""
+        )
+
+        self._try_markdown(markdown2html, case, output_check)
+
     def _try_markdown(self, method, test, tokens):
         results = method(test)
         if isinstance(tokens, (str,)):
diff --git a/share/templates/classic/index.html.j2 b/share/templates/classic/index.html.j2
index ec575b220..87a8578ac 100644
--- a/share/templates/classic/index.html.j2
+++ b/share/templates/classic/index.html.j2
@@ -19,6 +19,12 @@
 {%- block html_head_js_requirejs -%}
 <script src="{{ resources.require_js_url }}"></script>
 {%- endblock html_head_js_requirejs -%}
+{%- block html_head_js_mermaidjs -%}
+<script type="module">
+  import mermaid from '{{ resources.mermaid_js_url }}';
+  mermaid.initialize({ startOnLoad: true });
+</script>
+{%- endblock html_head_js_mermaidjs -%}
 {%- endblock html_head_js -%}
 
 {% block jupyter_widgets %}
diff --git a/share/templates/lab/index.html.j2 b/share/templates/lab/index.html.j2
index 4a6bb8663..8c5665298 100644
--- a/share/templates/lab/index.html.j2
+++ b/share/templates/lab/index.html.j2
@@ -1,5 +1,6 @@
 {%- extends 'base.html.j2' -%}
 {% from 'mathjax.html.j2' import mathjax %}
+{% from 'mermaidjs.html.j2' import mermaid_js %}
 {% from 'jupyter_widgets.html.j2' import jupyter_widgets %}
 
 {%- block header -%}
@@ -149,6 +150,10 @@ body[data-format='mobile'] .jp-OutputArea-child .jp-OutputArea-output {
 {{ mathjax(resources.mathjax_url) }}
 {%- endblock html_head_js_mathjax -%}
 
+{%- block html_head_js_mermaidjs -%}
+{{ mermaid_js(resources.mermaid_js_url) }}
+{%- endblock html_head_js_mermaidjs -%}
+
 {%- block html_head_css -%}
 {%- endblock html_head_css -%}
 
diff --git a/share/templates/lab/mermaidjs.html.j2 b/share/templates/lab/mermaidjs.html.j2
new file mode 100644
index 000000000..06c18479e
--- /dev/null
+++ b/share/templates/lab/mermaidjs.html.j2
@@ -0,0 +1,114 @@
+{%- macro mermaid_js(
+url="https://cdnjs.cloudflare.com/ajax/libs/mermaid/10.0.2/mermaid.esm.min.mjs"
+) -%}
+<script type="module">
+  document.addEventListener("DOMContentLoaded", async () => {
+    const diagrams = document.querySelectorAll(".jp-Mermaid > pre.mermaid");
+    // do not load mermaidjs if not needed
+    if (!diagrams.length) {
+      return;
+    }
+    const mermaid = (await import("{{ url }}")).default;
+
+    mermaid.initialize({
+      maxTextSize: 100000,
+      startOnLoad: false,
+      fontFamily: window
+        .getComputedStyle(document.body)
+        .getPropertyValue("--jp-ui-font-family"),
+      theme: document.querySelector("body[data-jp-theme-light='true']")
+        ? "default"
+        : "dark",
+    });
+
+    let _nextMermaidId = 0;
+
+    function makeMermaidImage(svg) {
+      const img = document.createElement('img');
+      const maxWidth = svg.match(/max-width: (\d+)/);
+      if (maxWidth && maxWidth[1]) {
+        const width = parseInt(maxWidth[1]);
+        if (width && !Number.isNaN(width) && Number.isFinite(width)) {
+          img.width = width;
+        }
+      }
+      img.setAttribute('src', `data:image/svg+xml,${encodeURIComponent(svg)}`);
+      return img;
+    }
+
+    async function makeMermaidError(text) {
+      let errorMessage = '';
+      try {
+        await mermaid.parse(text);
+      } catch (err) {
+        errorMessage = `${err}`;
+      }
+
+      const result = document.createElement('details');
+      const summary = document.createElement('summary');
+      const pre = document.createElement('pre');
+      const code = document.createElement('code');
+      code.innerText = text;
+      pre.appendChild(code);
+      summary.appendChild(pre);
+      result.appendChild(summary);
+
+      const warning = document.createElement('pre');
+      warning.innerText = errorMessage;
+      result.appendChild(warning);
+      return result;
+    }
+
+    async function renderOneMarmaid(src) {
+      const id = `jp-mermaid-${_nextMermaidId++}`;
+      const parent = src.parentNode;
+      let raw = src.textContent.trim();
+      const el = document.createElement("div");
+      el.style.visibility = "hidden";
+      document.body.appendChild(el);
+      let result = null;
+      try {
+        const { svg } = await mermaid.render(id, raw, el);
+        result = makeMermaidImage(svg);
+      } catch (err) {
+        parent.classList.add("jp-mod-warning");
+        result = await makeMermaidError(raw);
+      } finally {
+        el.remove();
+      }
+      parent.classList.add("jp-RenderedMermaid");
+      parent.appendChild(result);
+    }
+
+    void Promise.all([...diagrams].map(renderOneMarmaid));
+  });
+</script>
+<style>
+  .jp-RenderedMarkdown .jp-Mermaid:not(.jp-RenderedMermaid) {
+    display: none;
+  }
+  .jp-RenderedMarkdown .jp-RenderedMermaid.jp-mod-warning {
+    width: auto;
+    padding: 10px;
+    border: var(--jp-border-width) solid var(--jp-warn-color2);
+    border-radius: var(--jp-border-radius);
+    color: var(--jp-ui-font-color1);
+    font-size: var(--jp-ui-font-size1);
+    white-space: pre-wrap;
+    word-wrap: break-word;
+  }
+  .jp-RenderedMarkdown .jp-RenderedMermaid.jp-mod-warning details > pre {
+    margin-top: 1em;
+  }
+  .jp-RenderedMarkdown .jp-RenderedMermaid.jp-mod-warning summary {
+    color: var(--jp-warn-color2);
+  }
+  .jp-RenderedMarkdown .jp-RenderedMermaid.jp-mod-warning summary > pre {
+    display: inline-block;
+  }
+  .jp-RenderedMermaid > .mermaid {
+    display: none;
+  }
+</style>
+<!-- End of mermaid configuration -->
+{%- endmacro %}
diff --git a/share/templates/reveal/index.html.j2 b/share/templates/reveal/index.html.j2
index c30af4b4f..84cb65280 100644
--- a/share/templates/reveal/index.html.j2
+++ b/share/templates/reveal/index.html.j2
@@ -30,6 +30,12 @@
 {%- block html_head_js_requirejs -%}
 <script src="{{ resources.require_js_url }}"></script>
 {%- endblock html_head_js_requirejs -%}
+{%- block html_head_js_mermaidjs -%}
+<script type="module">
+  import mermaid from '{{ resources.mermaid_js_url }}';
+  mermaid.initialize({ startOnLoad: true });
+</script>
+{%- endblock html_head_js_mermaidjs -%}
 {%- endblock html_head_js -%}
 
 {% block jupyter_widgets %}