diff --git a/appveyor.yml b/appveyor.yml
index f044adb..9cf3107 100644
--- a/appveyor.yml
+++ b/appveyor.yml
@@ -57,7 +57,7 @@ install:
 
   # Upgrade to the latest version of pip to avoid it displaying warnings
   # about it being out of date.
-  - "pip install --disable-pip-version-check --user --upgrade pip"
+  - "python -m pip install --disable-pip-version-check --user --upgrade pip"
 
   # Install the build dependencies of the project. If some dependencies contain
   # compiled extensions and are not provided as pre-built wheel packages,