diff --git a/CHANGES.md b/CHANGES.md
index 10aabd33..abf4a7cd 100644
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -2,6 +2,7 @@
 
 ## python-markdown2 2.5.6 (not yet released)
 
+- [pull #776] Support `~~~` fences in the `fenced-code-blocks` extra
 - [pull #762] Speed up documents with many links by skipping the backslash-escape scan for text without a backslash
 - [pull #748] Speed up `_unescape_special_chars` by skipping text with no hashes and dropping the full-text comparison per pass (#635)
 - [pull #749] URL-encode destinations generated by the `link-patterns` extra (#55)
diff --git a/lib/markdown2.py b/lib/markdown2.py
index d6285404..839f8063 100755
--- a/lib/markdown2.py
+++ b/lib/markdown2.py
@@ -3704,13 +3704,13 @@ class FencedCodeBlocks(Extra):
 
     fenced_code_block_re = re.compile(r'''
         (?:\n+|\A\n?|(?<=\n))
-        (^[ \t]*`{3,})\s{0,99}?([\w+\#.-]+)?\s{0,99}?\n  # $1 = opening fence (captured for back-referencing), $2 = optional lang
+        (^[ \t]*(?:`{3,}|~{3,}))\s{0,99}?([\w+\#.-]+)?\s{0,99}?\n  # $1 = opening fence (captured for back-referencing), $2 = optional lang
         (.*?)                             # $3 = code block content
-        ^[ ]{0,3}\1`*[ \t]*\n           # closing fence
+        ^[ ]{0,3}\1[`~]*[ \t]*\n         # closing fence
         ''', re.M | re.X | re.S)
 
     def test(self, text: str):
-        if '```' not in text:
+        if '```' not in text and '~~~' not in text:
             return False
         if self.md.stage == Stage.PREPROCESS and not self.md.safe_mode:
             # if safe mode is off then run before HASH_HTML and not worry about the tags getting messed up
diff --git a/test/tm-cases/fenced_code_blocks_tilde.html b/test/tm-cases/fenced_code_blocks_tilde.html
new file mode 100644
index 00000000..38bf4831
--- /dev/null
+++ b/test/tm-cases/fenced_code_blocks_tilde.html
@@ -0,0 +1,11 @@
+<p>Run:</p>
+
+<pre><code>ls ~/x
+</code></pre>
+
+<p>And with backticks inside:</p>
+
+<pre><code>```
+not a fence
+```
+</code></pre>
diff --git a/test/tm-cases/fenced_code_blocks_tilde.opts b/test/tm-cases/fenced_code_blocks_tilde.opts
new file mode 100644
index 00000000..c02a10d8
--- /dev/null
+++ b/test/tm-cases/fenced_code_blocks_tilde.opts
@@ -0,0 +1 @@
+{"extras": ["fenced-code-blocks", "strike"]}
diff --git a/test/tm-cases/fenced_code_blocks_tilde.tags b/test/tm-cases/fenced_code_blocks_tilde.tags
new file mode 100644
index 00000000..0edfe9c0
--- /dev/null
+++ b/test/tm-cases/fenced_code_blocks_tilde.tags
@@ -0,0 +1 @@
+extra fenced-code-blocks strike
diff --git a/test/tm-cases/fenced_code_blocks_tilde.text b/test/tm-cases/fenced_code_blocks_tilde.text
new file mode 100644
index 00000000..30ca335d
--- /dev/null
+++ b/test/tm-cases/fenced_code_blocks_tilde.text
@@ -0,0 +1,13 @@
+Run:
+
+~~~
+ls ~/x
+~~~
+
+And with backticks inside:
+
+~~~
+```
+not a fence
+```
+~~~