This thesis examines the impact of external actors’ involvement on regional organizations’ mediation duration. Focusing on the context of Africa, the study employs a qualitative comparative analysis of two mediation cases to explore the causal relationship between extensive external actors’ involvement and mediation duration. The analysis draws on vastly collected qualitative data from various sources, including reports, news articles, practitioners’ memoirs, and other relevant publications. The finding reveals that extensive external actors’ involvement in regional organizations’ mediation process prolonged mediation duration, while modest external actors’ involvement is linked to a relatively shorter mediation duration. The prolonged mediation duration is attributed to factors such as competition among external actors, coordination challenges, lack of timely decision-making, and the initiation of parallel mediations. The implication of the findings contributes to a better understanding of the dynamics between external actors’ involvement and regional organizations’ mediation processes. It highlights the need for effective cooperation of external actors to enhance regional organizations’ mediation efficiency.