diff --git a/docs/format-changelog.rst b/docs/format-changelog.rst
index 1a70a8a..19b9e09 100644
--- a/docs/format-changelog.rst
+++ b/docs/format-changelog.rst
@@ -48,3 +48,12 @@ Changed behavior
 
 - Using ``multiconfig:*`` targets adds appropriate ``BBMULTICONFIG`` entries to
   the ``local.conf`` automatically.
+
+Version 6
+---------
+
+Added
+~~~~~
+
+- ``env`` key now allows to pass custom environment variables to the bitbake
+  build process.
diff --git a/docs/userguide.rst b/docs/userguide.rst
index ce9f89b..79b6228 100644
--- a/docs/userguide.rst
+++ b/docs/userguide.rst
@@ -294,6 +294,11 @@ Configuration reference
     ``core-image-minimal``. Space is used as a delimiter if multiple targets
     should be specified via the environment variable.
 
+* ``env``: dict [optional]
+    Contains environment variable names with the default values. These
+    variables are made available to bitbake via ``BB_ENV_EXTRAWHITE`` and can
+    be overwritten by the variables of the environment in which kas is started.
+
 * ``task``: string [optional]
     Contains the task to build by bitbake. Can be overwritten by the
     ``KAS_TASK`` environment variable and defaults to ``build``.
diff --git a/kas/__version__.py b/kas/__version__.py
index 998ff8a..3f3a66c 100644
--- a/kas/__version__.py
+++ b/kas/__version__.py
@@ -28,5 +28,5 @@ __copyright__ = 'Copyright (c) Siemens AG, 2017'
 __version__ = '0.14.0'
 
 # Please update docs/format-changelog.rst when changing the file version.
-__file_version__ = 5
+__file_version__ = 6
 __compatible_file_version__ = 1
diff --git a/kas/config.py b/kas/config.py
index 51005ba..510e424 100644
--- a/kas/config.py
+++ b/kas/config.py
@@ -277,6 +277,14 @@ class Config:
         return os.environ.get('KAS_DISTRO',
                               self._config.get('distro', 'poky'))
 
+    def get_environment(self):
+        """
+            Returns the configured environment variables from the configuration
+            file, with possible overwritten values from the environment.
+        """
+        env = self._config.get('env', {})
+        return {var: os.environ.get(var, env[var]) for var in env}
+
     def get_multiconfig(self):
         """
             Returns the multiconfig array as bitbake string
diff --git a/kas/configschema.py b/kas/configschema.py
index 36ac67c..2d1e2ab 100644
--- a/kas/configschema.py
+++ b/kas/configschema.py
@@ -78,6 +78,12 @@ CONFIGSCHEMA = {
         'distro': {
             'type': 'string',
         },
+        'env': {
+            'type': 'object',
+            'additionalProperties': {
+                'type': 'string',
+            },
+        },
         'target': {
             'oneOf': [
                 {
diff --git a/kas/libkas.py b/kas/libkas.py
index 36c42dd..461b396 100644
--- a/kas/libkas.py
+++ b/kas/libkas.py
@@ -306,7 +306,13 @@ def get_build_environ(config, build_dir):
         except ValueError:
             pass
 
+    conf_env = config.get_environment()
+
     env_vars = ['SSTATE_DIR', 'DL_DIR', 'TMPDIR']
+    env_vars.extend(conf_env)
+
+    env.update(conf_env)
+
     if 'BB_ENV_EXTRAWHITE' in env:
         extra_white = env['BB_ENV_EXTRAWHITE'] + ' '.join(env_vars)
         env.update({'BB_ENV_EXTRAWHITE': extra_white})