diff --git a/NEWS b/NEWS
index 2414f89..86f8588 100644
--- a/NEWS
+++ b/NEWS
@@ -3,6 +3,7 @@ Changes from 0.12.1
    [ Language Changes ]
    * `let` has been removed. Python's scoping rules do not make a proper
      implementation of it possible. Use `setv` instead.
+   * Commas and underscores are allowed in numeric literals
    * xor: If exactly one argument is true, return it
 
    [ Bug Fixes ]
diff --git a/docs/language/api.rst b/docs/language/api.rst
index 0b68f90..ba1fe5f 100644
--- a/docs/language/api.rst
+++ b/docs/language/api.rst
@@ -18,7 +18,7 @@ These rules help ensure that Hy code is idiomatic and interfaceable in both
 languages.
 
 
-  * Symbols in earmufs will be translated to the upper-cased version of that
+  * Symbols in earmuffs will be translated to the upper-cased version of that
     string. For example, ``foo`` will become ``FOO``.
 
   * UTF-8 entities will be encoded using
@@ -34,10 +34,8 @@ languages.
 Notes on Syntax
 ===============
 
-integers
---------
-
-.. versionadded:: 0.11.1
+numeric literals
+----------------
 
 In addition to regular numbers, standard notation from Python 3 for non-base 10
 integers is used. ``0x`` for Hex, ``0o`` for Octal, ``0b`` for Binary.
@@ -46,6 +44,13 @@ integers is used. ``0x`` for Hex, ``0o`` for Octal, ``0b`` for Binary.
     
     (print 0x80 0b11101 0o102 30)
 
+Underscores and commas can appear anywhere in a numeric literal. They have no
+effect on the value of the literal, but they're useful for visually separating
+digits.
+
+.. code-block:: clj
+
+    (print 10,000,000,000 10_000_000_000)
 
 Built-Ins
 =========
diff --git a/hy/models/complex.py b/hy/models/complex.py
index aead797..d45ce6f 100644
--- a/hy/models/complex.py
+++ b/hy/models/complex.py
@@ -19,6 +19,7 @@
 # DEALINGS IN THE SOFTWARE.
 
 from hy.models import HyObject, _wrappers
+from hy._compat import string_types
 
 
 class HyComplex(HyObject, complex):
@@ -28,6 +29,8 @@ class HyComplex(HyObject, complex):
     """
 
     def __new__(cls, number, *args, **kwargs):
+        if isinstance(number, string_types):
+            number = number.replace("_", "").replace(",", "")
         number = complex(number)
         return super(HyComplex, cls).__new__(cls, number)
 
diff --git a/hy/models/float.py b/hy/models/float.py
index 1632963..4669ff2 100644
--- a/hy/models/float.py
+++ b/hy/models/float.py
@@ -19,6 +19,7 @@
 # DEALINGS IN THE SOFTWARE.
 
 from hy.models import HyObject, _wrappers
+from hy._compat import string_types
 
 
 class HyFloat(HyObject, float):
@@ -28,6 +29,8 @@ class HyFloat(HyObject, float):
     """
 
     def __new__(cls, number, *args, **kwargs):
+        if isinstance(number, string_types):
+            number = number.replace("_", "").replace(",", "")
         number = float(number)
         return super(HyFloat, cls).__new__(cls, number)
 
diff --git a/hy/models/integer.py b/hy/models/integer.py
index f54727b..e780b26 100644
--- a/hy/models/integer.py
+++ b/hy/models/integer.py
@@ -19,7 +19,7 @@
 # DEALINGS IN THE SOFTWARE.
 
 from hy.models import HyObject, _wrappers
-from hy._compat import long_type, str_type
+from hy._compat import long_type, string_types
 
 import sys
 
@@ -32,7 +32,8 @@ class HyInteger(HyObject, long_type):
     """
 
     def __new__(cls, number, *args, **kwargs):
-        if isinstance(number, str_type):
+        if isinstance(number, string_types):
+            number = number.replace("_", "").replace(",", "")
             bases = {"0x": 16, "0o": 8, "0b": 2}
             for leader, base in bases.items():
                 if number.startswith(leader):
diff --git a/tests/lex/test_lex.py b/tests/lex/test_lex.py
index cc9e7cc..881eef2 100644
--- a/tests/lex/test_lex.py
+++ b/tests/lex/test_lex.py
@@ -143,6 +143,32 @@ def test_lex_expression_complex():
     assert objs == [HyExpression([HySymbol("foo"), HySymbol("j")])]
 
 
+def test_lex_digit_separators():
+
+    assert tokenize("1_000_000") == [HyInteger(1000000)]
+    assert tokenize("1,000,000") == [HyInteger(1000000)]
+    assert tokenize("1,000_000") == [HyInteger(1000000)]
+    assert tokenize("1_000,000") == [HyInteger(1000000)]
+
+    assert tokenize("0x_af") == [HyInteger(0xaf)]
+    assert tokenize("0x,af") == [HyInteger(0xaf)]
+    assert tokenize("0b_010") == [HyInteger(0b010)]
+    assert tokenize("0b,010") == [HyInteger(0b010)]
+    assert tokenize("0o_373") == [HyInteger(0o373)]
+    assert tokenize("0o,373") == [HyInteger(0o373)]
+
+    assert tokenize('1_2.3,4') == [HyFloat(12.34)]
+    assert tokenize('1_2e3,4') == [HyFloat(12e34)]
+    assert (tokenize("1,2/3_4") ==
+            [HyExpression([HySymbol("fraction"),
+             HyInteger(12), HyInteger(34)])])
+    assert tokenize("1,0_00j") == [HyComplex(1000j)]
+
+    assert tokenize(",,,,___,__1__,,__,,2__,,,__") == [HyInteger(12)]
+    assert (tokenize(",,,,___,__1__,,__,,2__,q,__") ==
+            [HySymbol(",,,,___,__1__,,__,,2__,q,__")])
+
+
 def test_lex_line_counting():
     """ Make sure we can count lines / columns """
     entry = tokenize("(foo (one two))")[0]