diff --git a/docs/CMakeLists.txt b/docs/CMakeLists.txt
index dd7cd84c..c7410441 100644
--- a/docs/CMakeLists.txt
+++ b/docs/CMakeLists.txt
@@ -43,8 +43,6 @@ set(unitsSphinxDocs
     "${CMAKE_CURRENT_SOURCE_DIR}/_static/img/downcast_2.png"
     "${CMAKE_CURRENT_SOURCE_DIR}/_static/img/units.png"
 
-    "${CMAKE_CURRENT_SOURCE_DIR}/_themes/sphinx_rtd_theme.zip"
-
     "${CMAKE_CURRENT_SOURCE_DIR}/CHANGELOG.md"
 
     "${CMAKE_CURRENT_SOURCE_DIR}/design.rst"
diff --git a/docs/_themes/sphinx_rtd_theme.zip b/docs/_themes/sphinx_rtd_theme.zip
deleted file mode 100644
index 321f0e81..00000000
Binary files a/docs/_themes/sphinx_rtd_theme.zip and /dev/null differ
diff --git a/docs/conf.py b/docs/conf.py
index be014700..36168772 100644
--- a/docs/conf.py
+++ b/docs/conf.py
@@ -10,6 +10,7 @@
 """
 
 import re
+import sphinx_rtd_theme
 
 from pygments.lexer import RegexLexer, include, bygroups, using, \
     this, inherit, default, words
@@ -272,6 +273,7 @@ extensions = [
     'sphinx.ext.autosectionlabel',
     'sphinx.ext.githubpages',
     'sphinx.ext.graphviz',
+    'sphinx_rtd_theme',
     'recommonmark',
     'breathe'
 ]
@@ -323,11 +325,6 @@ cpp_index_common_prefix = ['units::']
 
 # -- Options for HTML output -------------------------------------------------
 
-# A list of paths that contain custom themes, either as subdirectories or as
-# zip files. Relative paths are taken as relative to the configuration directory.
-
-html_theme_path = ["_themes", ]
-
 # The theme to use for HTML and HTML Help pages.  See the documentation for
 # a list of builtin themes.
 html_theme = 'sphinx_rtd_theme'
diff --git a/docs/requirements.txt b/docs/requirements.txt
index 8fe35f85..17150963 100644
--- a/docs/requirements.txt
+++ b/docs/requirements.txt
@@ -1,3 +1,4 @@
 sphinx>=2.4.4
+sphinx_rtd_theme
 recommonmark
 breathe>=4.14.1