In modern research activities, scientific data sharing is essential in terms of data-intensive science and scholarly communication. Scientific communities are making continuous endeavors to promote scientific data sharing. Currently, however, it is not always well-deployed throughout science and engineering disciplines. The objective of this research is to investigate the factors which influence scientists' data sharing behaviors. Two theoretical perspectives, institutional theory and theory of planned behavior, are employed in developing a conceptual model, which shows the complementary nature of the institutional and individual factors influencing scientists' data sharing behaviors. Institutional theory can explain the context in which individual scientists are acting; whereas the theory of planned behavior can explain the underlying motivations behind scientists' data sharing behaviors in an institutional context. This research will use a survey method to investigate the data sharing factors at individual and institutional levels. The findings from this study have the potential to accelerate both scientific collaborations and further enable data-intensive scientific research. This research can provide useful guidelines for designing data sharing repositories, developing relevant policies for data sharing, and facilitating individual scientists' data sharing within different scientific communities.