diff --git a/appveyor.yml b/appveyor.yml
index e74e7b82..509a85e5 100644
--- a/appveyor.yml
+++ b/appveyor.yml
@@ -30,7 +30,7 @@ install:
       if (!([string]$version).endswith('0.9.0')) { $env:INSTALL_CBINDGEN=1 }
   - IF "%INSTALL_CBINDGEN%" == "1" cargo install cbindgen --version 0.9.0 --force
   - nuget install doxygen -Version 1.8.14
-  - py -3 -m pip install -r docs/requirements.txt
+  - py -3.7 -m pip install -r docs/requirements.txt
   - ps: (New-Object Net.WebClient).DownloadFile('https://raw.githubusercontent.com/Ortham/ci-scripts/2.1.3/delete_old_bintray_versions.py', "$env:APPVEYOR_BUILD_FOLDER\delete_old_bintray_versions.py")
   - ps: if ($env:PLATFORM -eq "Win32") { $env:ADDRESS_MODEL = '32' } else { $env:ADDRESS_MODEL = '64' }