: The rising spate of piracy in Nigeria's territorial waters has become a burden on the economic development of the country. It has adversely affected the exportation of crude oil, which is the mainstay of the country's economy. Pirates target and hijack vessels carrying oil and gas, thus reducing the revenue accruable to the country from selling these resources. Piracy also affects the fishing industry which is another source of revenue to the country. Nigeria, as an import dependent country, relies on the importation of finished goods, and this is seriously affected by piracy. This study briefly examines the root causes of piracy in Nigeria. Further, the study interrogates the effects of piracy, identifies the challenges in the suppression of the crime and proffers suggestions toward suppressing the crime in the country. Against this backdrop, the study argues, among other things, that an expansive definition of piracy is key in the fight against this maritime crime in Nigeria, because the present legal regime is restrictive and limited in scope, thus, it does not reflect the modern piratical acts. More importantly, Nigeria must criminalise piracy in its domestic law in other to police its territorial waters, capture and prosecute pirates in its local courts.