Inquiry-based instruction (IBI) is widely renowned as one of the best approaches to teaching school science. Nonetheless, while science teachers in Tanzania might involve in teaching activities consistent with inquiry, IBI is not yet recognised as a formal approach to teaching science. Hence, this study investigated the extent to which IBI is promoted in Tanzanian secondary science curriculum documents. Additionally, it proposed suggestions on how to adopt IBI in the context of Tanzania. Using document analysis as a method of inquiry, six syllabi for secondary school science subjects in Tanzania were analysed to assess the extent to which they support IBI practice. Further, curriculum documents for secondary school science from South Africa and the United States were also analysed. This was done so as to compare between education systems that have recognised IBI as a formal approach to teaching science with that of Tanzania. Results indicated that while teaching methods, goals and objectives of education support the practice of IBI, a few aspects such as the time allocated and resources suggested for accomplishing investigative learning activities are the barriers to practising IBI. By reflecting on these results and lessons learned from the US and South Africa, the study provides recommendations such as allocating enough time for carrying out scientific investigations, changing teachers’ beliefs, revision of some learning objectives, and promoting teacher professional development in case Tanzania wishes to adopt IBI.