diff --git a/Tools/autotest/bisect-helper.py b/Tools/autotest/bisect-helper.py
index 3858a53fb6..90f74dec69 100755
--- a/Tools/autotest/bisect-helper.py
+++ b/Tools/autotest/bisect-helper.py
@@ -1,4 +1,4 @@
-#!/usr/bin/env python
+#!/usr/bin/env python3
 
 '''A helper script for bisecting common problems when working with ArduPilot
 
diff --git a/Tools/environment_install/install-prereqs-windows-andAPMSource.ps1 b/Tools/environment_install/install-prereqs-windows-andAPMSource.ps1
index 2076ce1f58..5cc7735a5b 100644
--- a/Tools/environment_install/install-prereqs-windows-andAPMSource.ps1
+++ b/Tools/environment_install/install-prereqs-windows-andAPMSource.ps1
@@ -19,7 +19,7 @@ Start-Process -wait -FilePath "C:\cygwin64\bin\bash" -ArgumentList "--login -i -
 Start-Process -wait -FilePath "C:\cygwin64\bin\bash" -ArgumentList "--login -i -c 'ln -sf /usr/bin/pip3.7 /usr/bin/pip'"
 
 Write-Output "Downloading extra Python packages (5/8)"
-Start-Process -wait -FilePath "C:\cygwin64\bin\bash" -ArgumentList "--login -i -c 'pip install empy==3.3.4 pyserial pymavlink intelhex dronecan pexpect'"
+Start-Process -wait -FilePath "C:\cygwin64\bin\bash" -ArgumentList "--login -i -c 'python3.7 -m pip install empy==3.3.4 pyserial pymavlink intelhex dronecan pexpect'"
 
 Write-Output "Downloading APM source (6/8)"
 Copy-Item "APM_install.sh" -Destination "C:\cygwin64\home"
diff --git a/Tools/environment_install/install-prereqs-windows.ps1 b/Tools/environment_install/install-prereqs-windows.ps1
index 15bac62894..543f1370c9 100644
--- a/Tools/environment_install/install-prereqs-windows.ps1
+++ b/Tools/environment_install/install-prereqs-windows.ps1
@@ -19,7 +19,7 @@ Start-Process -wait -FilePath "C:\cygwin64\bin\bash" -ArgumentList "--login -i -
 Start-Process -wait -FilePath "C:\cygwin64\bin\bash" -ArgumentList "--login -i -c 'ln -sf /usr/bin/pip3.7 /usr/bin/pip'"
 
 Write-Output "Downloading extra Python packages (5/7)"
-Start-Process -wait -FilePath "C:\cygwin64\bin\bash" -ArgumentList "--login -i -c 'pip install empy==3.3.4 pyserial pymavlink intelhex dronecan pexpect'"
+Start-Process -wait -FilePath "C:\cygwin64\bin\bash" -ArgumentList "--login -i -c 'python3.7 -m pip install empy==3.3.4 pyserial pymavlink intelhex dronecan pexpect'"
 
 Write-Output "Installing ARM GCC Compiler 10-2020-Q4-Major (6/7)"
 & $PSScriptRoot\gcc-arm-none-eabi-10-2020-q4-major-win32.exe /S /P /R
diff --git a/Tools/scripts/build_appveyor.sh b/Tools/scripts/build_appveyor.sh
index d392bbe4e0..e06ef2591a 100755
--- a/Tools/scripts/build_appveyor.sh
+++ b/Tools/scripts/build_appveyor.sh
@@ -18,7 +18,7 @@ cd /cygdrive/c/work
 
     ./waf configure --board sitl
 
-    /usr/bin/python waf -j4 copter plane rover heli sub
+    python3 waf -j4 copter plane rover heli sub
 
     # map to the names that MissionPlanner expects
     cp /cygdrive/c/work/build/sitl/bin/ardurover.exe /cygdrive/c/work/sitl/Rover.elf
diff --git a/Tools/scripts/filter_size_compare_branches_csv.py b/Tools/scripts/filter_size_compare_branches_csv.py
index 8030608c5e..aa42fa2a09 100755
--- a/Tools/scripts/filter_size_compare_branches_csv.py
+++ b/Tools/scripts/filter_size_compare_branches_csv.py
@@ -1,4 +1,4 @@
-#!/usr/bin/python
+#!/usr/bin/env python3
 
 import argparse
 import csv