diff --git a/INSTALL.rst b/INSTALL.rst
index 882e8e1661c5657b2a794460b82f1b770be83bfd..ad6419cb71c104c11914ff0dd098b11c28770a0f 100644
--- a/INSTALL.rst
+++ b/INSTALL.rst
@@ -188,7 +188,7 @@ root.
 1. Install the required packages.  On Debian-based systems like Ubuntu this can
    be done by running the command ::
 
-       sudo apt-get install python3-dev python3-scipy python3-matplotlib python3-pytest g++ gfortran libopenblas-dev liblapack-dev libmumps-scotch-dev
+       sudo apt-get install python3-dev python3-scipy python3-matplotlib python3-pytest python3-sympy g++ gfortran libopenblas-dev liblapack-dev libmumps-scotch-dev
 
 2. Unpack Tinyarray, enter its directory. To build and install, run ::