diff --git a/Dockerfile b/Dockerfile
index df93220a7d..6c9bcfa57c 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -1,4 +1,4 @@
-FROM python:slim
+FROM python:3.8-slim
 
 RUN apt-get update && apt-get install -y --no-install-recommends \
         curl \
@@ -9,8 +9,8 @@ RUN apt-get update && apt-get install -y --no-install-recommends \
         software-properties-common \
         && apt-get clean && rm -rf /var/lib/apt/lists/* /tmp/*
 
-RUN pip3 install --no-cache-dir --no-binary :all: \
-        sphinx
+COPY requirements.txt .
+RUN pip3 install --no-cache-dir --no-binary :all: -r requirements.txt
 
 EXPOSE 8000
 WORKDIR /data/esphomedocs
diff --git a/requirements.txt b/requirements.txt
index d77eea84f3..a20f2ded52 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -1 +1 @@
-sphinx>=1.8.4
+sphinx==4.0.3