The military coup in Guinea-Bissau that ousted President João Bernardo Vieira marked a pivotal moment in the country's turbulent political history. The roots of the coup lay deep in a backdrop of political strife, marked by economic challenges and a loss of public confidence in Vieira's leadership. Tensions were heightened due to ongoing disputes with military officials and the public's growing dissatisfaction with government corruption. In early May 1999, these tensions escalated into a violent confrontation as military forces launched a surprise attack against Vieira's government offices and residences.

Amidst gunfire and chaos, the military took control of the capital, Bissau, quickly overpowering government loyalists. Vieira, who had previously been a prominent figure in Guinea-Bissau's independence struggle and political landscape, found himself isolated as key military leaders denounced his leadership. The coup was completed within hours, demonstrating the fragile nature of power in a nation that had struggled with coups and attempted coups since gaining independence from Portugal in 1974.

Following the coup, the military established a transitional government, which was recognized by several international organizations. However, the events initiated a period of instability that would lead to further conflicts in the country. The coup's aftermath saw shifts in political alliances and continued economic challenges, which shaped Guinea-Bissau's future governance for years to come.