Tax enforcement is an integral part of the tax system as it compels and ensures compliance with tax laws. Under the Nigerian tax laws, enforcement can be carried out through civil action by tax authorities to recover tax owed, criminal prosecution of defaulters, imposition of fines, distrain of property, chattels and bonds and sealing of the business premises of a defaulting taxpayer. However, it would appear that the efficacy of these enforcement mechanisms is in doubt in view of the low level of tax compliance in the country. Through the doctrinal research method, this paper has revealed that the tax authorities in Nigeria prefer civil action against tax defaulters just to recover tax owed without criminal prosecution which has been shown to be more effective as deterrence to crime. It has also shown that enforcement through distrain and sealing of property and premises may inhibit the productive capacity of the taxpayer. In terms of tax enforcement against a foreign tax defaulter who is not resident in Nigeria, the paper has revealed that the Nigerian tax enforcement mechanism is helpless as foreign tax laws and judgments are not enforceable in the forum. The paper therefore recommends criminal prosecution of tax defaulters and increase in fines to serve as deterrence to tax defaulters. It also recommends a multilateral convention seeking the recognition and enforcement of foreign tax laws and judgments abroad so that a defaulting foreign taxpayer who has found his way back home can be proceeded against in his home country.