Despite growing policy commitments to equality, inclusion, and human rights, many African societies continue to experience persistent challenges such as discrimination, social exclusion, gender inequality, ethnic tensions, and unequal educational opportunities. These challenges highlight the need for educational approaches that promote diversity, social justice, and social cohesion. This study explored the potential of Competency-Based Curriculum (CBC) to advance diversity and social justice in Africa, with particular focus on East Africa, and developed an African-centered conceptual model to guide curriculum development. The study employed a systematic literature review and qualitative document analysis of curriculum frameworks, policy documents, scholarly literature, and reports from international and regional organizations. The analysis examined contemporary perspectives on curriculum reform, inclusive education, social justice, diversity, and competency-based learning. Findings indicate that diversity and social justice can be effectively integrated into CBC through inclusive curriculum content, learner-centered and transformative pedagogies, values and competency development, inclusive assessment practices, teacher preparation, and community engagement. Based on these findings, the study proposes the African Diversity and Social Justice Curriculum Model (ADSJCM), a conceptual framework comprising six interconnected components designed to support the development of inclusive, equitable, and socially responsive education systems. The study concludes that curriculum reform grounded in African realities and competency-based principles can play a critical role in fostering social cohesion, inclusion, democratic participation, and sustainable development across the continent.