The study aims at examining libraries in four Sub-Saharan Africa countries and their role in propagating open science. It also seeks to explore existing open science practices, ascertain the level of participation of academic libraries in open science activities, identify the strategies used in marketing open science platforms and enumerate the challenges hindering the success of open science in the selected countries. The study was guided by the qualitative school of thought where the researcher builds a complex, holistic picture, analyses words, and reports detailed views of informants, and conducts the study in a natural setting. The study employed the multiple case study research design approach to assess how academic libraries in Ghana, Nigeria, Tanzania and Uganda promote open science. The findings show that there are few scholarly journals which exist in open access for most African academies in Ghana, Nigeria, Tanzania and Uganda. Though not massively adopted, open access institutional repositories have been used to preserve and publicize the digital contents in some academic institutions in Africa such as theses, dissertations, administrative and heritage materials, conference proceedings as well as pre-prints and post-print of journal articles. The study recommends the intensification of open science advocacy in academic libraries in Sub-Saharan Africa; institutions should ensure that there is a stable electricity supply as well as reliable internet connectivity, introducing regular training on emerging media technologies to the community members and strengthening the libraries consortium in Sub-Saharan Africa as an enabling platform to share intellectual productivity of their member countries.