diff --git a/poetry/core/packages/directory_dependency.py b/poetry/core/packages/directory_dependency.py
index d0cbf2523..184f534a2 100644
--- a/poetry/core/packages/directory_dependency.py
+++ b/poetry/core/packages/directory_dependency.py
@@ -10,6 +10,7 @@
     from .constraints import BaseConstraint  # noqa
 
 from .dependency import Dependency
+from .utils.utils import path_to_url
 
 
 class DirectoryDependency(Dependency):
@@ -121,7 +122,8 @@ def base_pep_508_name(self) -> str:
         if self.extras:
             requirement += "[{}]".format(",".join(self.extras))
 
-        requirement += " @ {}".format(self._path.as_posix())
+        path = path_to_url(self.path) if self.path.is_absolute() else self.path
+        requirement += " @ {}".format(path)
 
         return requirement