The political parties of the First Republic (1960–1966) are most heavily criticised for being ethnically based and regionally focused. Instead of operating as national entities with a broad country-wide appeal, the three major parties were tied directly to specific regions and ethnic groups:

• NPC (Northern People's Congress): Rooted in the Northern Region and primarily representing Hausa-Fulani interests.

• NCNC (National Council of Nigerian Citizens): While initially more national, it became increasingly associated with the Eastern Region and the Igbo people.

• AG (Action Group): Based in the Western Region and largely representing Yoruba interests.

This "tripartite federal structure" led to a "winner-takes-all" political culture where parties prioritised their own regions over national unity, ultimately resulting in the political instability that led to the 1966 coup.