Socio-scientific issues have become increasingly important in Science-Technology-Society (STS) education as a means to make science learning more relevant to students' lives. This study used the e-waste issue as a context to investigate two aspects of socio-scientific decision-making: (1) the relationship between the nature of science (NOS) conceptualizations and decision-making; and (2) moral concerns involved in the process of decision-making. This study contributes to the field of socio-scientific issue research and STS education in the following ways. First, it is the first study that performed meta-analysis to seek the relationship between the NOS understanding and decision-making. This study concludes that valuable NOS conceptualizations that are highly related to the socio-scientific issue under investigation, rather than general NOS understanding, exert statistically significant influences on decision-making. Second, this study empirically examined the Multiple Responses Model (MRM), which enables the transfer of qualitative NOS responses into quantitative data, and hence, inferential statistics. The current study justifies the significance of unidimensionality to the application of the MRM. It addresses the limitations associated with the MRM and provides implications for future use of the MRM in other contexts. Finally, the study explores the role of moral concerns in socio-scientific decision-making. Eight participants engaged in interviews that were designed to elicit their reactions and feelings regarding the issue of exporting e-waste to poor countries. Qualitative analyses demonstrated that moral considerations were significant influences on decision-making. In addition, participants' action responses revealed that they were motivated to take action to help the environment. The study has implications for socio-scientific issue studies in other contexts and for teacher education programs that use socio-scientific issues to advance teachers' reasoning and discourse skills. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]