diff --git a/Dockerfile b/Dockerfile
index dcb1f55..f855dfb 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -55,7 +55,7 @@ WORKDIR /opt/maubot
 RUN apk add --virtual .build-deps python3-dev build-base git \
     && sed -Ei 's/psycopg2-binary.+//' optional-requirements.txt \
     && pip3 install -r requirements.txt -r optional-requirements.txt \
-        dateparser langdetect python-gitlab pyquery \
+        dateparser langdetect python-gitlab pyquery cchardet \
     && apk del .build-deps
 # TODO also remove dateparser, langdetect and pyquery when maubot supports installing dependencies
 
diff --git a/Dockerfile.ci b/Dockerfile.ci
index 9746683..494b7f5 100644
--- a/Dockerfile.ci
+++ b/Dockerfile.ci
@@ -49,7 +49,7 @@ WORKDIR /opt/maubot
 RUN apk add --virtual .build-deps python3-dev build-base git \
     && sed -Ei 's/psycopg2-binary.+//' optional-requirements.txt \
     && pip3 install -r requirements.txt -r optional-requirements.txt \
-        dateparser langdetect python-gitlab pyquery \
+        dateparser langdetect python-gitlab pyquery cchardet \
     && apk del .build-deps
 # TODO also remove dateparser, langdetect and pyquery when maubot supports installing dependencies