diff --git a/bison/__version__.py b/bison/__version__.py
index c2e3d74..7228c96 100644
--- a/bison/__version__.py
+++ b/bison/__version__.py
@@ -3,7 +3,7 @@
 __title__ = 'bison'
 __description__ = 'Python application configuration'
 __url__ = 'https://github.com/edaniszewski/bison'
-__version__ = '0.0.4'
+__version__ = '0.0.5'
 __author__ = 'Erick Daniszewski'
 __author_email__ = 'edaniszewski@gmail.com'
 __license__ = 'MIT'
diff --git a/bison/bison.py b/bison/bison.py
index f1b30f9..445f61e 100644
--- a/bison/bison.py
+++ b/bison/bison.py
@@ -86,10 +86,10 @@ class Bison(object):
         """
         if self._full_config is None:
             self._full_config = DotDict()
-            self._full_config.update(self._default)
-            self._full_config.update(self._config)
-            self._full_config.update(self._environment)
-            self._full_config.update(self._override)
+            self._full_config.merge(self._default)
+            self._full_config.merge(self._config)
+            self._full_config.merge(self._environment)
+            self._full_config.merge(self._override)
         return self._full_config
 
     def get(self, key, default=None):
diff --git a/bison/utils.py b/bison/utils.py
index f2065b9..ac706f5 100644
--- a/bison/utils.py
+++ b/bison/utils.py
@@ -6,6 +6,8 @@ bison.utils
 Utilities for `bison`.
 """
 
+import collections
+
 
 def build_dot_value(key, value):
     """Build new dictionaries based off of the dot notation key.
@@ -167,3 +169,69 @@ class DotDict(dict):
                     raise KeyError(
                         'Subkey "{}" in "{}" invalid for deletion'.format(k, key)
                     )
+
+    def merge(self, source):
+        """Merge the dictionary with the values from another dictionary
+        (or other DotDict).
+
+        This is preferable to using `update` in some cases. Merging will recursively
+        update a dictionary, while updating will just overwrite. As an example, if
+        we have the DotDict with the values
+
+            >>> d = DotDict({
+            ...   'foo': {
+            ...     'bar': True
+            ...   }
+            ... })
+            >>> d
+            {'foo': {'bar': True}}
+
+        Then for update, we would get:
+
+            >>> d.update({'foo': {'baz': False}})
+            >>> d
+            {'foo': {'baz': False}}
+
+        For a merge, we would get:
+
+            >>> d.merge({'foo': {'baz': False}})
+            >>> d
+            {'foo': {'bar': True, 'baz': False}}
+
+        So, an `update` will replace the specified dictionary, but a `merge` will
+        combine the values.
+
+        Args:
+            source: The dict/iterable which will be used to update the DotDict.
+        """
+        _merge(self, source)
+
+
+def _merge(d, u):
+    """Merge two dictionaries (or DotDicts) together.
+
+    Args:
+          d: The dictionary/DotDict to merge into.
+          u: The source of the data to merge.
+    """
+    for k, v in u.items():
+        # if we have a mapping, recursively merge the values
+        if isinstance(v, collections.Mapping):
+            d[k] = _merge(d.get(k, {}), v)
+
+        # if d (the dict to merge into) is a dict, just add the
+        # value to the dict.
+        elif isinstance(d, collections.MutableMapping):
+            d[k] = v
+
+        # otherwise if d (the dict to merge into) is not a dict (e.g. when
+        # recursing into it, `d.get(k, {})` may not be a dict), then do what
+        # `update` does and prefer the new value.
+        #
+        # this means that something like `{'foo': 1}` when updated with
+        # `{'foo': {'bar': 1}}` would have the original value (`1`) overwritten
+        # and would become: `{'foo': {'bar': 1}}`
+        else:
+            d = {k: v}
+
+    return d
diff --git a/tests/test_bison.py b/tests/test_bison.py
index 5fe50f5..0d49351 100644
--- a/tests/test_bison.py
+++ b/tests/test_bison.py
@@ -111,6 +111,118 @@ class TestBison:
             }
         }
 
+    def test_set_multiple_nested_2(self):
+        """Set overrides for multiple nested values when some already exist."""
+        b = bison.Bison()
+        assert len(b._override) == 0
+        assert len(b.config) == 0
+
+        # set the override config config to something to begin
+        b._override = bison.DotDict({
+            'foo': 'bar',
+            'bar': {
+                'bat': {
+                    'a': 'test'
+                },
+                'bird': {
+                    'b': 'test'
+                }
+            }
+        })
+
+        b.set('foo', 'baz')
+        assert b.config == {
+            'foo': 'baz',
+            'bar': {
+                'bat': {
+                    'a': 'test'
+                },
+                'bird': {
+                    'b': 'test'
+                }
+            }
+        }
+
+        b.set('bar.bat.a', None)
+        assert b.config == {
+            'foo': 'baz',
+            'bar': {
+                'bat': {
+                    'a': None
+                },
+                'bird': {
+                    'b': 'test'
+                }
+            }
+        }
+
+        b.set('bar.bird', 'warbler')
+        assert b.config == {
+            'foo': 'baz',
+            'bar': {
+                'bat': {
+                    'a': None
+                },
+                'bird': 'warbler'
+            }
+        }
+
+    def test_set_multiple_nested_3(self):
+        """Set overrides for multiple nested values when some already exist."""
+        b = bison.Bison()
+        assert len(b._override) == 0
+        assert len(b.config) == 0
+
+        # set a non override config config to something to begin
+        b._config = bison.DotDict({
+            'foo': 'bar',
+            'bar': {
+                'bat': {
+                    'a': 'test'
+                },
+                'bird': {
+                    'b': 'test'
+                }
+            }
+        })
+
+        b.set('foo', 'baz')
+        assert b.config == {
+            'foo': 'baz',
+            'bar': {
+                'bat': {
+                    'a': 'test'
+                },
+                'bird': {
+                    'b': 'test'
+                }
+            }
+        }
+
+        b.set('bar.bat.a', None)
+        assert b.config == {
+            'foo': 'baz',
+            'bar': {
+                'bat': {
+                    'a': None
+                },
+                'bird': {
+                    'b': 'test'
+                }
+            }
+        }
+
+        b.set('bar.bird', 'warbler')
+        assert b.config == {
+            'foo': 'baz',
+            'bar': {
+                'bat': {
+                    'a': None
+                },
+                'bird': 'warbler'
+            }
+        }
+
     @pytest.mark.parametrize(
         'paths', [
             (),
diff --git a/tests/test_utils.py b/tests/test_utils.py
index fdd3fde..ae32a9d 100644
--- a/tests/test_utils.py
+++ b/tests/test_utils.py
@@ -391,3 +391,107 @@ class TestDotDict:
             }
         })
         assert (key in dd) is expected
+
+    @pytest.mark.parametrize(
+        'source,expected', [
+            ({}, {'foo': 'bar', 'bar': {'baz': {'key': 'value'}}}),
+            ({'foo': 'test'}, {'foo': 'test', 'bar': {'baz': {'key': 'value'}}}),
+            ({'abc': '123'}, {'foo': 'bar', 'abc': '123', 'bar': {'baz': {'key': 'value'}}}),
+            ({'bar': 'test'}, {'foo': 'bar', 'bar': 'test'}),
+            ({'bar': {'test': 'value'}}, {'foo': 'bar', 'bar': {'test': 'value'}}),
+            ({'test': 123}, {'foo': 'bar', 'test': 123, 'bar': {'baz': {'key': 'value'}}}),
+            ({'foo': 123}, {'foo': 123, 'bar': {'baz': {'key': 'value'}}}),
+            ({'bar': 123}, {'foo': 'bar', 'bar': 123}),
+            ({'test': [1, 2, 3]}, {'foo': 'bar', 'test': [1, 2, 3], 'bar': {'baz': {'key': 'value'}}}),
+            ({'foo': [1, 2, 3]}, {'foo': [1, 2, 3], 'bar': {'baz': {'key': 'value'}}}),
+            ({'bar': [1, 2, 3]}, {'foo': 'bar', 'bar': [1, 2, 3]}),
+            ({'test': {'a': 1}}, {'foo': 'bar', 'test': {'a': 1}, 'bar': {'baz': {'key': 'value'}}}),
+            ({'foo': {'a': 1}}, {'foo': {'a': 1}, 'bar': {'baz': {'key': 'value'}}}),
+            ({'bar': {'a': 1}}, {'foo': 'bar', 'bar': {'a': 1}}),
+            ({'test': False}, {'foo': 'bar', 'test': False, 'bar': {'baz': {'key': 'value'}}}),
+            ({'foo': False}, {'foo': False, 'bar': {'baz': {'key': 'value'}}}),
+            ({'bar': False}, {'foo': 'bar', 'bar': False}),
+            ({'test': None}, {'foo': 'bar', 'test': None, 'bar': {'baz': {'key': 'value'}}}),
+            ({'foo': None}, {'foo': None, 'bar': {'baz': {'key': 'value'}}}),
+            ({'bar': None}, {'foo': 'bar', 'bar': None}),
+        ]
+    )
+    def test_update(self, source, expected):
+        """Update the DotDict"""
+        dd = utils.DotDict({
+            'foo': 'bar',
+            'bar': {
+                'baz': {
+                    'key': 'value'
+                }
+            }
+        })
+        dd.update(source)
+        assert dd == expected
+
+    @pytest.mark.parametrize(
+        'source,expected', [
+            ({}, {'foo': 'bar', 'bar': {'baz': {'key': 'value'}}}),
+            ({'foo': 'test'}, {'foo': 'test', 'bar': {'baz': {'key': 'value'}}}),
+            ({'abc': '123'}, {'foo': 'bar', 'abc': '123', 'bar': {'baz': {'key': 'value'}}}),
+            ({'bar': 'test'}, {'foo': 'bar', 'bar': 'test'}),
+            ({'bar': {'test': 'value'}}, {'foo': 'bar', 'bar': {'baz': {'key': 'value'}, 'test': 'value'}}),
+            ({'test': 123}, {'foo': 'bar', 'test': 123, 'bar': {'baz': {'key': 'value'}}}),
+            ({'foo': 123}, {'foo': 123, 'bar': {'baz': {'key': 'value'}}}),
+            ({'bar': 123}, {'foo': 'bar', 'bar': 123}),
+            ({'test': [1, 2, 3]}, {'foo': 'bar', 'test': [1, 2, 3], 'bar': {'baz': {'key': 'value'}}}),
+            ({'foo': [1, 2, 3]}, {'foo': [1, 2, 3], 'bar': {'baz': {'key': 'value'}}}),
+            ({'bar': [1, 2, 3]}, {'foo': 'bar', 'bar': [1, 2, 3]}),
+            ({'test': {'a': 1}}, {'foo': 'bar', 'test': {'a': 1}, 'bar': {'baz': {'key': 'value'}}}),
+            ({'foo': {'a': 1}}, {'foo': {'a': 1}, 'bar': {'baz': {'key': 'value'}}}),
+            ({'bar': {'a': 1}}, {'foo': 'bar', 'bar': {'a': 1, 'baz': {'key': 'value'}}}),
+            ({'test': False}, {'foo': 'bar', 'test': False, 'bar': {'baz': {'key': 'value'}}}),
+            ({'foo': False}, {'foo': False, 'bar': {'baz': {'key': 'value'}}}),
+            ({'bar': False}, {'foo': 'bar', 'bar': False}),
+            ({'test': None}, {'foo': 'bar', 'test': None, 'bar': {'baz': {'key': 'value'}}}),
+            ({'foo': None}, {'foo': None, 'bar': {'baz': {'key': 'value'}}}),
+            ({'bar': None}, {'foo': 'bar', 'bar': None}),
+        ]
+    )
+    def test_merge(self, source, expected):
+        """Update the DotDict"""
+        dd = utils.DotDict({
+            'foo': 'bar',
+            'bar': {
+                'baz': {
+                    'key': 'value'
+                }
+            }
+        })
+        dd.merge(source)
+        assert dd == expected
+
+    def test_deep_merge(self):
+        """Test merging through many nested dicts."""
+        dd = utils.DotDict({
+            'foo': {
+                'bar': {
+                    'baz': {
+                        'bison': True
+                    }
+                }
+            }
+        })
+        dd.merge({'foo': {
+            'bar': {
+                'baz': {
+                    'birds': False
+                }
+            }
+        }})
+
+        assert dd == {
+            'foo': {
+                'bar': {
+                    'baz': {
+                        'bison': True,
+                        'birds': False
+                    }
+                }
+            }
+        }