diff --git a/kas/libcmds.py b/kas/libcmds.py
index 98507f7..0a148f4 100644
--- a/kas/libcmds.py
+++ b/kas/libcmds.py
@@ -260,6 +260,16 @@ class WriteBBConfig(Command):
         return 'write_bbconfig'
 
     def execute(self, ctx):
+        def _get_layer_path_under_topdir(ctx, layer):
+            """
+                Returns a path relative to ${TOPDIR}.
+                TOPDIR is a BB variable pointing to the build directory.
+                It is not expanded by KAS, hence we avoid
+                absolute paths pointing into the build host.
+            """
+            relpath = os.path.relpath(layer, ctx.build_dir)
+            return '${TOPDIR}/' + relpath
+
         def _write_bblayers_conf(ctx):
             filename = ctx.build_dir + '/conf/bblayers.conf'
             if not os.path.isdir(os.path.dirname(filename)):
@@ -268,7 +278,8 @@ class WriteBBConfig(Command):
                 fds.write(ctx.config.get_bblayers_conf_header())
                 fds.write('BBLAYERS ?= " \\\n    ')
                 fds.write(' \\\n    '.join(
-                    sorted(layer for repo in ctx.config.get_repos()
+                    sorted(_get_layer_path_under_topdir(ctx, layer)
+                           for repo in ctx.config.get_repos()
                            for layer in repo.layers)))
                 fds.write('"\n')
                 fds.write('BBPATH ?= "${TOPDIR}"\n')
diff --git a/tests/test_layers.py b/tests/test_layers.py
index 6981abc..4ccb208 100644
--- a/tests/test_layers.py
+++ b/tests/test_layers.py
@@ -26,6 +26,8 @@ from kas import kas
 
 import pytest
 
+LAYERBASE = '${TOPDIR}/..'
+
 
 @pytest.fixture
 def dokas(tmpdir):
@@ -42,7 +44,7 @@ def test_layers_default(dokas):
     match = 0
     with open('build/conf/bblayers.conf', 'r') as f:
         for line in f:
-            if 'test_layers/kas ' in line:
+            if '{}/kas '.format(LAYERBASE) in line:
                 match += 1
     assert(match == 1)
 
@@ -51,7 +53,7 @@ def test_layers_include(dokas):
     match = 0
     with open('build/conf/bblayers.conf', 'r') as f:
         for line in f:
-            if 'test_layers/kas1/meta-' in line:
+            if '{}/kas1/meta-'.format(LAYERBASE) in line:
                 match += 1
     assert(match == 2)
 
@@ -59,11 +61,11 @@ def test_layers_include(dokas):
 def test_layers_exclude(dokas):
     with open('build/conf/bblayers.conf', 'r') as f:
         for line in f:
-            assert('test_layers/kas2' not in line)
+            assert('{}/kas2'.format(LAYERBASE) not in line)
 
 
 def test_layers_strip_dot(dokas):
     with open('build/conf/bblayers.conf', 'r') as f:
         lines = f.readlines()
-        assert(any('test_layers/kas3 ' in x for x in lines))
-        assert(any('test_layers/kas3/meta-bar' in x for x in lines))
+        assert(any('{}/kas3 '.format(LAYERBASE) in x for x in lines))
+        assert(any('{}/kas3/meta-bar'.format(LAYERBASE) in x for x in lines))