diff --git a/plugins/python-build/bin/python-build b/plugins/python-build/bin/python-build
index 783848dc..95d56af2 100755
--- a/plugins/python-build/bin/python-build
+++ b/plugins/python-build/bin/python-build
@@ -2037,14 +2037,23 @@ build_package_get_pip() {
   build_package_symlink_version_suffix
 }
 
+# Pip <21 (in 2.7 and derivatives like PyPy-2.7) doesn't support -I
+build_package_ensurepip_lt21() {
+  build_package_ensurepip lt21
+}
+
 build_package_ensurepip() {
+  local mode="$1"
   local ensurepip_opts
   # Install as `--altinstall` if the Python is installed as `altinstall` (#255)
   if [[ "$PYTHON_MAKE_INSTALL_TARGET" == *"altinstall"* ]]; then
     ensurepip_opts="--altinstall"
   fi
+  local python_opts="-I"
+  if [[ $mode == "lt21" ]]; then python_opts="-s"; fi
+  
   # FIXME: `--altinstall` with `get-pip.py`
-  "$PYTHON_BIN" -I -m ensurepip ${ensurepip_opts} 1>/dev/null 2>&1 || build_package_get_pip "$@" || return 1
+  "$PYTHON_BIN" $python_opts -m ensurepip ${ensurepip_opts} 1>/dev/null 2>&1 || build_package_get_pip "$@" || return 1
   build_package_symlink_version_suffix
 }
 
diff --git a/plugins/python-build/share/python-build/2.7.18 b/plugins/python-build/share/python-build/2.7.18
index 5725575d..6576ca67 100644
--- a/plugins/python-build/share/python-build/2.7.18
+++ b/plugins/python-build/share/python-build/2.7.18
@@ -2,7 +2,7 @@ export PYTHON_BUILD_HOMEBREW_OPENSSL_FORMULA="openssl@1.1 openssl@1.0 openssl"
 install_package "openssl-1.1.1v" "https://www.openssl.org/source/openssl-1.1.1v.tar.gz" mac_openssl --if has_broken_mac_openssl
 install_package "readline-8.0" "https://ftpmirror.gnu.org/readline/readline-8.0.tar.gz#e339f51971478d369f8a053a330a190781acb9864cf4c541060f12078948e461" mac_readline --if has_broken_mac_readline
 if has_tar_xz_support; then
-  install_package "Python-2.7.18" "https://www.python.org/ftp/python/2.7.18/Python-2.7.18.tar.xz#b62c0e7937551d0cc02b8fd5cb0f544f9405bafc9a54d3808ed4594812edef43" standard verify_py27 copy_python_gdb ensurepip
+  install_package "Python-2.7.18" "https://www.python.org/ftp/python/2.7.18/Python-2.7.18.tar.xz#b62c0e7937551d0cc02b8fd5cb0f544f9405bafc9a54d3808ed4594812edef43" standard verify_py27 copy_python_gdb ensurepip_lt21
 else
-  install_package "Python-2.7.18" "https://www.python.org/ftp/python/2.7.18/Python-2.7.18.tgz#da3080e3b488f648a3d7a4560ddee895284c3380b11d6de75edb986526b9a814" standard verify_py27 copy_python_gdb ensurepip
+  install_package "Python-2.7.18" "https://www.python.org/ftp/python/2.7.18/Python-2.7.18.tgz#da3080e3b488f648a3d7a4560ddee895284c3380b11d6de75edb986526b9a814" standard verify_py27 copy_python_gdb ensurepip_lt21
 fi
diff --git a/plugins/python-build/share/python-build/pypy2.7-7.3.13 b/plugins/python-build/share/python-build/pypy2.7-7.3.13
index 627ffc42..0239066b 100644
--- a/plugins/python-build/share/python-build/pypy2.7-7.3.13
+++ b/plugins/python-build/share/python-build/pypy2.7-7.3.13
@@ -78,4 +78,4 @@ function pypy_pkg_data {
 declare -a pd="$(pypy_pkg_data "$(pypy_architecture 2>/dev/null || true)")"
 
 # install
-${pd[0]} "${pd[1]}" "${pd[2]}" 'pypy' "verify_py${PYVER//./}" 'ensurepip'
+${pd[0]} "${pd[1]}" "${pd[2]}" 'pypy' "verify_py${PYVER//./}" 'ensurepip_lt21'
diff --git a/plugins/python-build/share/python-build/pypy2.7-7.3.13-src b/plugins/python-build/share/python-build/pypy2.7-7.3.13-src
index 275d8091..4704161e 100644
--- a/plugins/python-build/share/python-build/pypy2.7-7.3.13-src
+++ b/plugins/python-build/share/python-build/pypy2.7-7.3.13-src
@@ -11,4 +11,4 @@ url="https://downloads.python.org/pypy/${ver}.tar.bz2"
 
 prefer_openssl11
 install_package "openssl-1.1.1f" "https://www.openssl.org/source/openssl-1.1.1f.tar.gz#186c6bfe6ecfba7a5b48c47f8a1673d0f3b0e5ba2e25602dd23b629975da3f35" mac_openssl --if has_broken_mac_openssl
-install_package "${ver}" "${url}#${hash}" 'pypy_builder' "verify_py${PYVER//./}" 'ensurepip'
+install_package "${ver}" "${url}#${hash}" 'pypy_builder' "verify_py${PYVER//./}" 'ensurepip_lt21'