diff --git a/.dockerignore b/.dockerignore
index c0d8a84b5..f44f6f853 100644
--- a/.dockerignore
+++ b/.dockerignore
@@ -12,6 +12,11 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+# Python virtual environments — never copy into Docker images
+.venv
+venv
+env/
+
 # Misc
 .git
 tmp