Does a US citizen need a VISA to travel to Morocco?

Visa and Entry/Exit Requirements for Morocco

The short answer: visa not required for stays up to 3 months.

According to the US consulate web site:

ENTRY REQUIREMENT: The Moroccan Immigration authorities require that U.S. citizens possess a valid passport to enter the country (student and military identity cards are not accepted). At present, vaccinations are not required. Upon your arrival, you may be asked to produce evidence that you have financial resources sufficient to cover your expenses during your stay in Morocco. LENGTH OF STAY: Although entry visas are not required, you must declare your intention to become a resident within 15 days of your arrival or depart Morocco three months after your arrival. Failure to comply with the three month regulation may result in prosecution by Moroccan authorities.