diff --git a/const_bsds.go b/const_bsds.go
index 9717374..5728243 100644
--- a/const_bsds.go
+++ b/const_bsds.go
@@ -11,7 +11,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-// +build darwin openbsd freebsd
+// +build darwin openbsd freebsd netbsd dragonfly
 
 package afero
 
diff --git a/const_win_unix.go b/const_win_unix.go
index d8f392b..968fc27 100644
--- a/const_win_unix.go
+++ b/const_win_unix.go
@@ -13,6 +13,8 @@
 // +build !darwin
 // +build !openbsd
 // +build !freebsd
+// +build !dragonfly
+// +build !netbsd
 
 package afero