diff --git a/appveyor.yml b/appveyor.yml
index 09f26584..01d40195 100644
--- a/appveyor.yml
+++ b/appveyor.yml
@@ -55,6 +55,7 @@ install:
     - ninja --version
     - python -m pip install --upgrade pip
     - pip3.exe install conan==1.24.1
+    - pip3.exe install lxml
     - cd %APPVEYOR_BUILD_FOLDER%
 
 before_build:
diff --git a/ci/install.sh b/ci/install.sh
index 929b01de..7419bc26 100755
--- a/ci/install.sh
+++ b/ci/install.sh
@@ -16,12 +16,14 @@ if [[ "$(uname -s)" == 'Linux' ]]; then
     source conan/bin/activate
     pip install conan==1.22.0
     pip install codecov
+    pip install lxml
 else
     sudo pip3 install virtualenv
     virtualenv conan
     source conan/bin/activate
     pip3 install conan==1.22.0
     pip3 install codecov
+    pip3 install lxml
 fi
 
 conan --version