diff --git a/sonic-slave-buster/Dockerfile.j2 b/sonic-slave-buster/Dockerfile.j2
index 66bc0564ef..18f7405bc7 100644
--- a/sonic-slave-buster/Dockerfile.j2
+++ b/sonic-slave-buster/Dockerfile.j2
@@ -57,6 +57,7 @@ RUN apt-get update && apt-get install -y \
         libtinyxml2-dev \
         python \
         python-pip \
+        python3 \
         python3-pip \
         libncurses5-dev \
         texinfo \
@@ -386,9 +387,11 @@ RUN apt-get install python-meld3
 
 # For vs image build
 RUN pip2 install pexpect==4.6.0
+RUN pip3 install pexpect==4.8.0
 
 # For sonic-swss-common testing
 RUN pip2 install Pympler==0.8
+RUN pip3 install Pympler==0.8
 
 # For sonic_yang_model build
 RUN pip2 install pyang==2.1.1