Scientific literacy (SL) has been recognized as the main goal of science curricula documents around the world; however, comparative international curriculum research is limited, especially with Western and African countries. To fill this gap, this study aimed to compare the coverage of SL competencies with the components of knowledge, attitudes, and contexts in the upper secondary school biology curricula of Finland and Nigeria. Content analysis was used as a method and a modified version of the SL framework of the Programme for International Student Assessment 2015 (OECD, 2016) was used to analyze the curricula. The results revealed that both curricula contain the main components of SL defined in the framework, scientific knowledge being the most prominent, followed by scientific competencies. Both curricula laid less emphasis on the interpretation competency and attitudes to science component. The curricula differed in the amount of attention paid to the different areas of SL components. The Finnish curriculum focused more on content knowledge, explaining phenomena scientifically and frontiers of science and technology, while in the Nigerian curriculum procedural knowledge, evaluation and design of scientific enquiry and natural resources as context were more emphasized. The results of this study are not only important to the European and African continents but to other parts of the world for the promotion SL in schools, also the findings reinforce the call on curriculum planers and science educators to ensure equal coverage of all the dimensions of SL in the school science curriculum if the next generation of the world is to be scientifically literate.