diff --git a/docs/INSTALL.md b/docs/INSTALL.md
index d830b68..d926ee1 100644
--- a/docs/INSTALL.md
+++ b/docs/INSTALL.md
@@ -24,7 +24,7 @@ is actually newer in version number, than what was there already.
 
 To install everything (client and server), install these packages:
 
-    sudo apt-get install python3-dev python3-pip git build-essential automake pkg-config libtool libffi-dev libssl-dev libgmp-dev
+    sudo apt-get install python3-dev python3-pip git build-essential automake pkg-config libtool libffi-dev libssl-dev
 
 (+ `libsodium-dev` if you can find it, else build after)
 
diff --git a/test/Dockerfiles/stretch-py3.Dockerfile b/test/Dockerfiles/stretch-py3.Dockerfile
index 8b644cf..f976f0b 100755
--- a/test/Dockerfiles/stretch-py3.Dockerfile
+++ b/test/Dockerfiles/stretch-py3.Dockerfile
@@ -5,7 +5,7 @@ SHELL ["/bin/bash", "-c"]
 RUN apt-get update
 RUN apt-get install -y build-essential
 RUN apt-get install -y \
-    automake pkg-config libtool libgmp-dev
+    automake pkg-config libtool
 RUN apt-get install -y \
     python3-dev python3-pip virtualenv python3-pyqt4 python3-sip
 
diff --git a/test/Dockerfiles/xenial-py3.Dockerfile b/test/Dockerfiles/xenial-py3.Dockerfile
index 0d56874..f3e9dad 100755
--- a/test/Dockerfiles/xenial-py3.Dockerfile
+++ b/test/Dockerfiles/xenial-py3.Dockerfile
@@ -5,7 +5,7 @@ SHELL ["/bin/bash", "-c"]
 RUN apt-get update
 RUN apt-get install -y build-essential
 RUN apt-get install -y \
-    automake pkg-config libtool libgmp-dev
+    automake pkg-config libtool
 RUN apt-get install -y \
     python3-dev python3-pip virtualenv python3-pyqt4 python3-sip