diff --git a/INSTALL.md b/INSTALL.md
index c8d7ac7..3d58446 100644
--- a/INSTALL.md
+++ b/INSTALL.md
@@ -9,6 +9,8 @@ For Pizza to work, you need a running mail service (either server, smarthost or
 ### The simple way
 
 Install Pizza by running "install.sh" from the base-directory.
+install.sh takes two arguments: PREFIX (defaults to "/usr/local/") and
+INCPREFIX (defaults to "$PREFIX/share"). To set INCPREFIX, passing PREFIX beforehands is mandatory!
 
 ### The hard way
 
@@ -20,4 +22,4 @@ mkdir -p $SHAREDIR/pizza
 install -m 644 assets/* $SHAREDIR/pizza/
 ```
 
-Afterwards, you have to set the variable `$PIZZAINC` to `$SHAREDIR` accordingly.
\ No newline at end of file
+Afterwards, you have to set the variable `$PIZZAINC` to `$SHAREDIR` accordingly.
diff --git a/install.sh b/install.sh
index c223806..b000307 100755
--- a/install.sh
+++ b/install.sh
@@ -6,29 +6,35 @@
 
 
 if [ "$1" ]; then
-	PREFIX:="$1"
+	PREFIX="$1"
 else
 	: ${PREFIX:="/usr/local"}
 fi
 
+if [ "$2" ]; then
+	INCPREFIX="$2"
+else
+	: ${INCPREFIX:="${PREFIX}/share"}
+fi
+
 # Create necessary directories
 
-for i in "${PREFIX}/bin" "${PREFIX}/share/pizza"; do
+for i in "${PREFIX}/bin" "${INCPREFIX}/share/pizza"; do
 	if [ ! -d "$i" ]; then
 		mkdir -p "$i"
 	fi
 done
 
 install -m 755 src/pizza "${PREFIX}/bin/pizza"
-install -m 644 assets/* "${PREFIX}/share/pizza/"
+install -m 644 assets/* "${INCPREFIX}/share/pizza/"
 
 # Tell the user what to do next, if he used another PREFIX
 
-if [ "${PREFIX}" != "/usr/local" ]; then
+if [ "${INCPREFIX}" != "/usr/local" ]; then
 	echo 'Your installation path differs from /usr/local'
 	echo 'For pizza to run properly, please either modify the script'
 	echo 'or set the PIZZAINC-variable accordingly.'
 	echo '(Add the following to your ${shell}rc:'
-	echo -e "\t export PIZZAINC=\"${PREFIX}/share/pizza/\""
+	echo -e "\t export PIZZAINC=\"${INCPREFIX}/pizza/\""
 	echo ")"
 fi