If you are a citizen of the European Union, you will only need a valid passport. For other countries, please find hereafter the link to the Moroccan Consulate. It discloses the list of countries exempted of visa entry in Morocco and all information to check out if you need a visa : <a href="http://www.moroccanconsulate.com/visa.cfm" target="_blank">http://www.moroccanconsulate.com/visa.cfm</a>
IMPORTANT : Passport and visa requirements are liable to change at short notice. You are strongly advised to check your entry requirements with your embassy or the consulate related to your own nationality. 