diff --git a/README b/README
index c8ac9c5f..c55533ba 100644
--- a/README
+++ b/README
@@ -45,7 +45,7 @@ ryandewhurst at gmail
 
   -> Installing on Debian/Ubuntu:
 
-    sudo apt-get install libcurl4-gnutls-dev libopenssl-ruby libxml2 libxml2-dev libxslt1-dev
+    sudo apt-get install libcurl4-gnutls-dev libopenssl-ruby libxml2 libxml2-dev libxslt1-dev ruby-dev
     git clone https://github.com/wpscanteam/wpscan.git
     cd wpscan
     sudo gem install bundler && bundle install --without test development
diff --git a/README.md b/README.md
index d7215b47..cf994ccf 100644
--- a/README.md
+++ b/README.md
@@ -38,7 +38,7 @@ Prerequisites:
 
 *Installing on Debian/Ubuntu:*
 
-```sudo apt-get install libcurl4-gnutls-dev libopenssl-ruby libxml2 libxml2-dev libxslt1-dev```
+```sudo apt-get install libcurl4-gnutls-dev libopenssl-ruby libxml2 libxml2-dev libxslt1-dev ruby-dev```
 
 ```git clone https://github.com/wpscanteam/wpscan.git```