diff --git a/docker/python-builder/Dockerfile b/docker/python-builder/Dockerfile
index 69676a2485..716aed202e 100644
--- a/docker/python-builder/Dockerfile
+++ b/docker/python-builder/Dockerfile
@@ -16,7 +16,9 @@
 FROM python:slim as fake-python
 
 WORKDIR /tmp
-RUN apt-get update && apt-get install -y equivs
+RUN apt-get update \
+  && apt-get install -y equivs \
+  && rm -rf /var/lib/apt/lists/*
 COPY python3-dev.control /tmp/python3-dev.control
 RUN equivs-build /tmp/python3-dev.control
 
@@ -28,4 +30,5 @@ COPY scripts/get-extras-packages /usr/local/bin/get-extras-packages
 COPY scripts/install-from-bindep /output/install-from-bindep
 RUN dpkg -i /tmp/python3-dev_4.0.0_all.deb \
   && rm /tmp/python3-dev_4.0.0_all.deb \
-  && pip install bindep
+  && pip install bindep \
+  && rm -rf /var/lib/apt/lists/*