Problem-solving skills are required to solve difficulties encountered in daily life. These skills are important but rarely mastered by fourth grade elementary school students. One explanation for this is that the learning tools have not been specifically designed to help pupils develop their problem-solving skills. The purpose of this research and development project was to generate a valid STEM-PBL module using the ADDIE procedure (analysis, design, development, implementation, and evaluation). The content validity was evaluated by a science learning expert, a learning technology expert, and a language expert. Construct validity was determined through an experimental study conducted with a group of students. The Likert scale was used to assess the product and the Content Validity Index (CVI) of the instrument was analyzed. The students� problem-solving skills were examined using a multiple choice test. The paired sample t-test was used to determine the differences in students� problem-solving skills following the module�s implementation. The STEM-PBL module was successfully developed for fourth graders of elementary school. This module integrates the STEM�s components as well as problem-based learning syntax. The module is arranged according to the characteristics of elementary school students, namely self-instruction, self-contained, stand alone, adaptive, and users friendly. The module was declared valid in terms of content by a science learning expert, a educational technology expert, and a linguist. The application of the module indicates differences in the research participants� pretest and post-test scores. The module includes practical tasks and problem-solving discussions that aid in the development of problem-solving skills. © 2022, Pegem Egitim ve Ogretim Dergisi. All Rights Reserved.