Abstract: Despite increasing recognition of Indigenous Knowledge (IK) as a resource for culturally relevant and context-based science education, less is known about how Biology teachers in Tanzanian secondary schools perceive its integration into ecology teaching. This study explored Biology teachers’ perceptions toward integrating Indigenous Knowledge in the teaching of ecology in selected secondary schools in Dodoma, Tanzania. Culturally Relevant Pedagogy guided the interpretation by emphasizing the importance of connecting formal learning with learners’ cultural backgrounds and community knowledge. This paper reports the teacher-focused component of a qualitative case study involving four Biology teachers from four secondary schools. Data were collected primarily through semi-structured interviews, with classroom observations and documentary review used to contextualise the teachers’ accounts, and were analysed through reflexive thematic analysis. The findings revealed that teachers generally perceived Indigenous Knowledge positively because they believed it could clarify ecological concepts through familiar examples, make lessons relevant and interesting, and promote appreciation of cultural and environmental knowledge. At the same time, teachers described practical barriers that limit consistent implementation, including inadequate teaching materials and curriculum guidance, limited professional preparation, and pressure to complete the Biology syllabus. The findings therefore reveal a clear gap between teachers’ positive beliefs about IK and the institutional conditions available for its classroom use. The study concludes that the participating teachers were willing to integrate Indigenous Knowledge into ecology teaching, but effective implementation requires systematic curriculum support, culturally relevant instructional resources, and sustained professional development.