Dissertation (MA Linguistics)The main concern of dissertation was language supportive input to science subjects learners in secondary schools in Zanzibar: Learners‟ weakness and the teachers‟ input. The study firstly explored the areas of difficult that science subjects learners in Zanzibar require language supportive input. Second, it examined the language supportive input provided by science teachers to science subjects students in secondary schools. Lastly, it assessed the science teachers‟ ability to provide language supportive input to science students. This study employed qualitative research technique and purposive sampling and stratified random sampling were used. The data were collected in the West District of Zanzibar through interviews, focus group discussion, observations and documentary reviews. The study was guided by the theory called Social Constructivism Theory of Language Learning. The findings of this study revealed that various areas of difficult that secondary school science students require language support in all four science subjects. Among the most mentioned areas in Mathematics are integers, bodmas, decimals, algebra, prime numbers and fraction. The findings also revealed that science teachers could not provide the language supportive inputs to science learners while teaching because they did not know how to provide them. Again, the findings revealed that science teachers have a minimum ability of providing language supportive inputs. Therefore, through this study; a further study is recommended to be done to examine the language supportive inputs to other subjects.