diff --git a/assertpy/assertpy.py b/assertpy/assertpy.py
index 51df162..019d951 100644
--- a/assertpy/assertpy.py
+++ b/assertpy/assertpy.py
@@ -685,6 +685,17 @@ def does_not_contain_entry(self, *entries):
                 self._err('Expected <%s> to not contain entry %s, but did.' % (self.val, e))
         return self
 
+### set assertions ###
+    def is_subset_of(self, superset):
+        """Asserts that val is a set and its items are contained within the set, 'superset'"""
+        if not isinstance(self.val, (set, frozenset)):
+            raise TypeError('val is not a set/frozenset')
+        if not isinstance(superset, (set, frozenset)):
+            raise TypeError('argument is not a set/frozenset')
+        if not self.val.issubset(superset):
+            self._err('Expected <%s> to be a subset of <%s>, but was not.' % (self.val, superset))
+        return self
+
 ### datetime assertions ###
     def is_before(self, other):
         """Asserts that val is a date and is before other date."""
diff --git a/tests/test_set.py b/tests/test_set.py
new file mode 100644
index 0000000..bcc1be0
--- /dev/null
+++ b/tests/test_set.py
@@ -0,0 +1,38 @@
+from assertpy import assert_that,fail
+
+class TestSet(object):
+
+    def test_val_type_error(self):
+        try:
+            assert_that(1).is_subset_of(set([1,2]))
+            fail('should have raised TypeError')
+        except TypeError:
+            pass
+
+    def test_arg_type_error(self):
+        try:
+            assert_that(set([])).is_subset_of(None)
+            fail('should have raised TypeError')
+        except TypeError:
+            pass
+
+    def test_val_edge_case(self):
+        assert_that(set()).is_subset_of(set([1,2,3]))
+
+    def test_arg_edge_case(self):
+        try:
+            assert_that(set([1,2,3])).is_subset_of(set())
+            fail('should have raised error')
+        except AssertionError as ex:
+            assert_that(str(ex)).is_equal_to('Expected <%s> to be a subset of <%s>, but was not.' % (set([1,2,3]), set()))
+
+    def test_positive_normal_case(self):
+        assert_that(set([1])).is_subset_of(set([1,2,3]))
+
+    def test_negative_normal_case(self):
+        try:
+            assert_that(set([1,2,3])).is_subset_of(set([1]))
+            fail('should have raised error')
+        except AssertionError as ex:
+            assert_that(str(ex)).is_equal_to('Expected <%s> to be a subset of <%s>, but was not.' % (set([1,2,3]), set([1])))
+