diff --git a/README.md b/README.md
index 73d9ad7..a61f5b7 100644
--- a/README.md
+++ b/README.md
@@ -19,16 +19,16 @@ Joinmarket is coinjoin software, and includes a wallet, which requires Bitcoin C
 
 Once you've downloaded this repo, either as a zip file, and extracted it, or via `git clone`:
 
-    ./install.sh -p python3
+    ./install.sh
     (follow instructions on screen; provide sudo password when prompted)
     source jmvenv/bin/activate
     cd scripts
 
-(You can omit `-p python3` if you want to use Python2. You can also add `--develop` as an extra flag to `install.sh` to make the Joinmarket code editable in-place.)
+(You can add `-p python2` if you want to use Python2. You can also add `--develop` as an extra flag to `install.sh` to make the Joinmarket code editable in-place.)
 
 For the Qt GUI, pass the `--with-qt` flag to `install.sh` as well :
 
-    ./install.sh -p python3 --with-qt
+    ./install.sh --with-qt
 
 Do note, Python 2 is incompatible with the Qt GUI.
 
diff --git a/install.sh b/install.sh
index 7d7b5ad..b4acaed 100755
--- a/install.sh
+++ b/install.sh
@@ -371,7 +371,7 @@ Usage: "${0}" [options]
 Options:
 
 --develop       code remains editable in place
---python, -p    python version (default: python2)
+--python, -p    python version (default: python3)
 --with-qt       build the Qt GUI (incompatible with python2)
 "
                 return 1
@@ -404,6 +404,9 @@ is_python3 ()
     if [[ ${python} == 'python3' ]]; then
         return 0
     fi
+    if [[ ${python} == 'python2' ]]; then
+        return 1
+    fi
     if eval "${python} -c 'import sys; sys.exit(0) if sys.version_info >= (3,0) else sys.exit(1)'"; then
         return 0
     else
@@ -442,7 +445,7 @@ main ()
     # flags
     develop_build=''
     no_gpg_validation=''
-    python='python2'
+    python='python3'
     with_qt=''
     reinstall='false'
     if ! parse_flags ${@}; then
diff --git a/test/Dockerfiles/bionic-py2.Dockerfile b/test/Dockerfiles/bionic-py2.Dockerfile
index 62729c0..4a43f3e 100755
--- a/test/Dockerfiles/bionic-py2.Dockerfile
+++ b/test/Dockerfiles/bionic-py2.Dockerfile
@@ -33,5 +33,5 @@ RUN bitcoind --version | head -1
 
 # install script
 WORKDIR ${repo_name}
-RUN ./install.sh
+RUN ./install.sh --python=python2
 RUN source jmvenv/bin/activate && ./test/run_tests.sh
diff --git a/test/Dockerfiles/centos7-py2.Dockerfile b/test/Dockerfiles/centos7-py2.Dockerfile
index b046f4e..732301b 100755
--- a/test/Dockerfiles/centos7-py2.Dockerfile
+++ b/test/Dockerfiles/centos7-py2.Dockerfile
@@ -29,5 +29,5 @@ RUN bitcoind --version | head -1
 
 # install script
 WORKDIR ${repo_name}
-RUN ./install.sh
+RUN ./install.sh --python=python2
 RUN source jmvenv/bin/activate && ./test/run_tests.sh
diff --git a/test/Dockerfiles/fedora27-py2.Dockerfile b/test/Dockerfiles/fedora27-py2.Dockerfile
index 15f05da..efe5044 100755
--- a/test/Dockerfiles/fedora27-py2.Dockerfile
+++ b/test/Dockerfiles/fedora27-py2.Dockerfile
@@ -32,5 +32,5 @@ RUN bitcoind --version | head -1
 
 # install script
 WORKDIR ${repo_name}
-RUN ./install.sh
+RUN ./install.sh --python=python2
 RUN source jmvenv/bin/activate && ./test/run_tests.sh
diff --git a/test/Dockerfiles/stretch-py2.Dockerfile b/test/Dockerfiles/stretch-py2.Dockerfile
index 8d5d31a..11d2ef9 100755
--- a/test/Dockerfiles/stretch-py2.Dockerfile
+++ b/test/Dockerfiles/stretch-py2.Dockerfile
@@ -33,5 +33,5 @@ RUN bitcoind --version | head -1
 
 # install script
 WORKDIR ${repo_name}
-RUN ./install.sh
+RUN ./install.sh --python=python2
 RUN source jmvenv/bin/activate && ./test/run_tests.sh
diff --git a/test/Dockerfiles/xenial-py2.Dockerfile b/test/Dockerfiles/xenial-py2.Dockerfile
index e248612..22e39a9 100755
--- a/test/Dockerfiles/xenial-py2.Dockerfile
+++ b/test/Dockerfiles/xenial-py2.Dockerfile
@@ -33,5 +33,5 @@ RUN bitcoind --version | head -1
 
 # install script
 WORKDIR ${repo_name}
-RUN ./install.sh
+RUN ./install.sh --python=python2
 RUN source jmvenv/bin/activate && ./test/run_tests.sh