diff --git a/gallery_dl/util.py b/gallery_dl/util.py
index 91fa0a61..0a263c01 100644
--- a/gallery_dl/util.py
+++ b/gallery_dl/util.py
@@ -1,6 +1,6 @@
 # -*- coding: utf-8 -*-
 
-# Copyright 2017-2018 Mike Fährmann
+# Copyright 2017-2019 Mike Fährmann
 #
 # This program is free software; you can redistribute it and/or modify
 # it under the terms of the GNU General Public License version 2 as
@@ -306,6 +306,10 @@ class Formatter():
         exceeds <maxlen>. Otherwise everything is left as is.
         Example: {f:L5/too long/} -> "foo"      (if "f" is "foo")
                                   -> "too long" (if "f" is "foobar")
+
+    - "J<separator>/":
+        Joins elements of a list (or string) using <separator>
+        Example: {f:J - /} -> "a - b - c" (if "f" is ["a", "b", "c"])
     """
     conversions = {
         "l": str.lower,
@@ -361,6 +365,8 @@ class Formatter():
                 func = self._format_optional
             elif format_spec[0] == "L":
                 func = self._format_maxlen
+            elif format_spec[0] == "J":
+                func = self._format_join
             else:
                 func = self._format_default
             fmt = func(format_spec)
@@ -419,6 +425,15 @@ class Formatter():
         maxlen = text.parse_int(maxlen[1:])
         return wrap
 
+    @staticmethod
+    def _format_join(format_spec):
+        def wrap(obj):
+            obj = separator.join(obj)
+            return format(obj, format_spec)
+        separator, _, format_spec = format_spec.partition("/")
+        separator = separator[1:]
+        return wrap
+
     @staticmethod
     def _format_default(format_spec):
         def wrap(obj):
diff --git a/test/test_util.py b/test/test_util.py
index 3a87757a..2a1909c0 100644
--- a/test/test_util.py
+++ b/test/test_util.py
@@ -1,7 +1,7 @@
 #!/usr/bin/env python3
 # -*- coding: utf-8 -*-
 
-# Copyright 2015-2018 Mike Fährmann
+# Copyright 2015-2019 Mike Fährmann
 #
 # This program is free software; you can redistribute it and/or modify
 # it under the terms of the GNU General Public License version 2 as
@@ -147,6 +147,7 @@ class TestFormatter(unittest.TestCase):
     kwdict = {
         "a": "hElLo wOrLd",
         "b": "äöü",
+        "l": ["a", "b", "c"],
         "u": "%27%3C%20/%20%3E%27",
         "name": "Name",
         "title1": "Title",
@@ -231,6 +232,18 @@ class TestFormatter(unittest.TestCase):
         self._run_test("{a:L50/foo/>51}", "foo")
         self._run_test("{a:Lab/foo/}", "foo")
 
+    def test_join(self):
+        self._run_test("{l:J}"       , "abc")
+        self._run_test("{l:J,}"      , "a,b,c")
+        self._run_test("{l:J,/}"     , "a,b,c")
+        self._run_test("{l:J,/>20}"  , "               a,b,c")
+        self._run_test("{l:J - }"    , "a - b - c")
+        self._run_test("{l:J - /}"   , "a - b - c")
+        self._run_test("{l:J - />20}", "           a - b - c")
+
+        self._run_test("{a:J/}"      , self.kwdict["a"])
+        self._run_test("{a:J, /}"    , ", ".join(self.kwdict["a"]))
+
     def _run_test(self, format_string, result, default=None):
         formatter = util.Formatter(format_string, default)
         output = formatter.format_map(self.kwdict)