diff --git a/pyproject.toml b/pyproject.toml
index b171ab6e..13cdcec4 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -58,6 +58,9 @@ classifiers = [
     "Topic :: Multimedia :: Graphics :: Viewers",
 ]
 
+[project.optional-dependencies]
+urwid = ["urwid>=2.1,<3.0"]
+
 [project.urls]
 Homepage = "https://github.com/AnonymouX47/term-image"
 Documentation = "https://term-image.readthedocs.io/"