diff --git a/docs/guide/install.rst b/docs/guide/install.rst
index 2c0a1134f..b69517076 100644
--- a/docs/guide/install.rst
+++ b/docs/guide/install.rst
@@ -125,6 +125,7 @@ Those developing Verilator itself may also want these (see internals.rst):
 ::
 
    sudo apt-get install gdb graphviz cmake clang clang-format-11 gprof lcov
+   sudo apt-get install yapf3
    sudo pip3 install sphinx sphinx_rtd_theme sphinxcontrib-spelling breathe
    cpan install Pod::Perldoc
    cpan install Parallel::Forker