In Nigeria, Sharia has been instituted as a main body of civil and criminal law in 9 Muslim-majority and in some parts of 3 Muslim-plurality states since 1999, when then-Zamfara State governor Ahmad Sani Yerima began the push for the institution of Sharia at the state level of government.
Twelve out of Nigeria's thirty-six states have Sunni Islam as the dominant religion. In 1999, those states chose to have Sharia courts as well as Customary courts.
As of 2012, the following 9 states have instituted Sharia:
the following 3 states have also instituted sharia in some parts with large Muslim populations
Some argue that as implemented in the north, Sharia violates the Constitution of Nigeria.
There have been numerous riots over the implementation of sharia law, primarily involving non-Muslim minorities in the states which implemented the system. One such riot killed over 100 people in October 2001 in Kano State.
In 2002, negative light was brought to sharia in northern Nigeria when Amina Lawal, a single mother in Katsina State, was accused of adultery and sentenced to death by stoning by a state Sharia court for conceiving a child out of wedlock; the father was released without conviction for lack of evidence. Lawal's conviction provoked outrage both in southern Nigeria and the West, with many national and international NGOs lobbying the federal government to overturn her conviction. In 2004, the conviction was overturned by the Sharia court of appeal, and Lawal returned to private life.
A Sharia court may treat blasphemy as deserving of several punishments up to, and including, execution. In many predominantly Muslim states, conversion from Islam to another religion is illegal and often a capital offence.
In 2014 a Nigerian man, Mubarak Bala was forcibly committed to a psychiatric institution in Kano for eighteen days, where he was forcibly drugged after stating that he was an atheist. The International Humanist and Ethical Union took up the case, stating that Bala's human rights were violated.
In 2002, the first execution of a man under Sharia took place in Katsina State; Human Rights Watch condemned the execution.