diff --git a/index.js b/index.js
index 43b1e50..094fc8f 100644
--- a/index.js
+++ b/index.js
@@ -72,6 +72,33 @@ const cleanRangeBackSlash = slashes => {
   return slashes.slice(0, length - length % 2)
 }
 
+// POSIX character classes ('[:alpha:]', '[:digit:]', ...) are part of the
+// wildmatch syntax gitignore uses, but JavaScript regular expressions have no
+// equivalent, so expand each one to its range (matching Git in the C locale).
+const POSIX_CLASS = {
+  alnum: '0-9A-Za-z',
+  alpha: 'A-Za-z',
+  blank: ' \\t',
+  cntrl: '\\x00-\\x1f\\x7f',
+  digit: '0-9',
+  graph: '\\x21-\\x7e',
+  lower: 'a-z',
+  print: '\\x20-\\x7e',
+  punct: '\\x21-\\x2f\\x3a-\\x40\\x5b-\\x60\\x7b-\\x7e',
+  space: ' \\t\\n\\x0b\\f\\r',
+  upper: 'A-Z',
+  xdigit: '0-9A-Fa-f'
+}
+
+const REGEX_POSIX_CLASS = /\[:([a-z]+):\]/g
+
+const expandPosixClasses = range => range.replace(
+  REGEX_POSIX_CLASS,
+  (match, name) => Object.prototype.hasOwnProperty.call(POSIX_CLASS, name)
+    ? POSIX_CLASS[name]
+    : match
+)
+
 // > If the pattern ends with a slash,
 // > it is removed for the purpose of the following description,
 // > but it would only find a match with a directory.
@@ -272,7 +299,9 @@ const REPLACERS = [
     // > can be used to match one of the characters in a range.
 
     // `\` is escaped by step 3
-    /(\\)?\[([^\]/]*?)(\\*)($|\])/g,
+    // A POSIX class '[:name:]' is consumed as a unit so its inner ']' is not
+    // mistaken for the end of the bracket expression.
+    /(\\)?\[((?:\[:[a-z]+:\]|[^\]/])*?)(\\*)($|\])/g,
     (match, leadEscape, range, endEscape, close) => leadEscape === ESCAPE
       // '\\[bar]' -> '\\\\[bar\\]'
       ? `\\[${range}${cleanRangeBackSlash(endEscape)}${close}`
@@ -281,7 +310,7 @@ const REPLACERS = [
           // A normal case, and it is a range notation
           // '[bar]'
           // '[bar\\\\]'
-          ? `[${negateRange(sanitizeRange(range))}${endEscape}]`
+          ? `[${expandPosixClasses(negateRange(sanitizeRange(range)))}${endEscape}]`
           // Invalid range notaton
           // '[bar\\]' -> '[bar\\\\]'
           : '[]'
diff --git a/test/fixtures/cases.js b/test/fixtures/cases.js
index 4720bea..6b6bc13 100644
--- a/test/fixtures/cases.js
+++ b/test/fixtures/cases.js
@@ -362,6 +362,58 @@ const cases = [
       'a.9': 0
     }
   ],
+  [
+    'POSIX class: [[:digit:]]',
+    [
+      '[[:digit:]].log'
+    ],
+    {
+      '1.log': 1,
+      'a.log': 0
+    }
+  ],
+  [
+    'POSIX class: [[:alpha:]]',
+    [
+      '[[:alpha:]].log'
+    ],
+    {
+      'a.log': 1,
+      '1.log': 0
+    }
+  ],
+  [
+    'POSIX class: negated [![:digit:]]',
+    [
+      'x[![:digit:]]'
+    ],
+    {
+      'xa': 1,
+      'x1': 0
+    }
+  ],
+  [
+    'POSIX class combined with a set: [[:alnum:]_]',
+    [
+      '[[:alnum:]_].o'
+    ],
+    {
+      'a.o': 1,
+      '_.o': 1,
+      '!.o': 0
+    }
+  ],
+  [
+    // An unknown class name is left as-is, matching Git (no match).
+    'POSIX class: unknown name is inert',
+    [
+      '[[:foo:]]'
+    ],
+    {
+      'foo': 0,
+      'f': 0
+    }
+  ],
   [
     // Just treat it as normal character set
     'special case: range-like character set',