The design and development of modules in cultivating entrepreneurial science thinking (EST) in STEM education at the primary school level is still limited. Thus, this research was conducted to: (1) establish the validity, reliability and feasibility of the module based on the socioscientific issues approach aided by the thinking wheel map (SIA-TM); and (2) evaluate its effects on the EST among fifth graders in STEM education. Data were collected via respondents' feedback in the 5-point Likert scale questionnaire and an EST test. The first phase of the module evaluation was conducted by five expert evaluators and among 30 fifth graders. The second phase was evaluation through the quasi-experimental research design with the pre-test post-test control group design. A total of 60 fifth graders were gathered into two groups which were the SIA-TM group (n=30) and control group (n=30). The results of the SIA-TM module evaluation shows that the validity value was good, and the alpha Cronbach reliability was between 0.74 and 0.89 with the overall value of 0.92. The students showed a high level of acceptance (m=4.53) towards the activities in the SIA-TM Module. Feedback from the students showed the module's feasibility and acceptance by students. The results of the t-test prove a significantly positive effect on the five constructs in EST. Therefore, these results establish that the SIA-TM teaching and learning module is valid, reliable, feasible and effective in increasing fifth graders' EST in STEM education.