The first coup in Nigeria was led by a group of military officers, with Major Chukwuma Nzeogu as the most prominent among them. The coup took place on January 15, 1966, and overthrew the democratically elected government of Prime Minister Abubakar Tafawa Balewa.
The coup was largely driven by a desire among some military officers to end corruption, tribalism, and political instability in Nigeria. The coup was also motivated by a sense of dissatisfaction among some younger officers who felt that their senior colleagues were blocking their opportunities for advancement.
After the coup, Major Nzeogu declared a new government, the National Council of Nigeria and the Cameroons (NCNC), and installed General Johnson Aguiyi-Ironsi as the new Head of State. However, the Ironsi-led government was short-lived, as it was overthrown in a counter-coup on July 29, 1966, led by northern officers who were unhappy with the dominance of the Igbo ethnic group in the military and the government.
The first coup in Nigeria had significant and long-lasting implications for the country, including several years of military rule, ethnic tensions, and a series of further coups and counter-coups that destabilized the country's politics for decades.