diff --git a/lexers/embedded/diff.xml b/lexers/embedded/diff.xml
index c10963e21..dc0beb7fd 100644
--- a/lexers/embedded/diff.xml
+++ b/lexers/embedded/diff.xml
@@ -14,6 +14,18 @@
       <rule pattern=" .*\n">
         <token type="Text"/>
       </rule>
+      <rule pattern="\d+(,\d+)?(a|c|d)\d+(,\d+)?\n">
+        <token type="GenericSubheading"/>
+      </rule>
+      <rule pattern="---\n">
+        <token type="GenericStrong"/>
+      </rule>
+      <rule pattern="&lt; .*\n">
+        <token type="GenericDeleted"/>
+      </rule>
+      <rule pattern="&gt; .*\n">
+        <token type="GenericInserted"/>
+      </rule>
       <rule pattern="\+.*\n">
         <token type="GenericInserted"/>
       </rule>
diff --git a/lexers/testdata/diff/default.actual b/lexers/testdata/diff/default.actual
new file mode 100644
index 000000000..37e44125b
--- /dev/null
+++ b/lexers/testdata/diff/default.actual
@@ -0,0 +1,9 @@
+1,2d0
+< A
+< A
+4c2
+< C
+---
+> F
+5a4
+> E
diff --git a/lexers/testdata/diff/default.expected b/lexers/testdata/diff/default.expected
new file mode 100644
index 000000000..9e29b15cd
--- /dev/null
+++ b/lexers/testdata/diff/default.expected
@@ -0,0 +1,10 @@
+[
+  {"type":"GenericSubheading","value":"1,2d0\n"},
+  {"type":"GenericDeleted","value":"\u003c A\n\u003c A\n"},
+  {"type":"GenericSubheading","value":"4c2\n"},
+  {"type":"GenericDeleted","value":"\u003c C\n"},
+  {"type":"GenericStrong","value":"---\n"},
+  {"type":"GenericInserted","value":"\u003e F\n"},
+  {"type":"GenericSubheading","value":"5a4\n"},
+  {"type":"GenericInserted","value":"\u003e E\n"}
+]
diff --git a/lexers/testdata/diff/unified.actual b/lexers/testdata/diff/unified.actual
new file mode 100644
index 000000000..dc7cf07c5
--- /dev/null
+++ b/lexers/testdata/diff/unified.actual
@@ -0,0 +1,10 @@
+--- old.txt	2023-01-17 21:02:15.449417575 -0700
++++ new.txt	2023-01-17 21:02:12.489441682 -0700
+@@ -1,5 +1,4 @@
+-A
+-A
+ B
+-C
++F
+ D
++E
diff --git a/lexers/testdata/diff/unified.expected b/lexers/testdata/diff/unified.expected
new file mode 100644
index 000000000..79c717c98
--- /dev/null
+++ b/lexers/testdata/diff/unified.expected
@@ -0,0 +1,11 @@
+[
+  {"type":"GenericDeleted","value":"--- old.txt\t2023-01-17 21:02:15.449417575 -0700\n"},
+  {"type":"GenericInserted","value":"+++ new.txt\t2023-01-17 21:02:12.489441682 -0700\n"},
+  {"type":"GenericSubheading","value":"@@ -1,5 +1,4 @@\n"},
+  {"type":"GenericDeleted","value":"-A\n-A\n"},
+  {"type":"Text","value":" B\n"},
+  {"type":"GenericDeleted","value":"-C\n"},
+  {"type":"GenericInserted","value":"+F\n"},
+  {"type":"Text","value":" D\n"},
+  {"type":"GenericInserted","value":"+E\n"}
+]