Problem-solving skills are advantageous when resolving complicated and multidimensional challenges. Problem-solving skills can be developed through active learning models that engage students in the learning process. One active learning model is RICOSRE. The main focus of RICOSRE is problem-solving activities in (1) reading; (2) identifying the problem; (3) constructing the solution; (4) solving the problem; (5) reviewing the solution; and (6) extending the solution. The purpose of this study was to assess the ongoing development of problem-solving skills of students with upper, middle, and lower academic abilities at the Department of Biology Education in a state university in Indonesia. This study employed a concurrent embedded mixed-methods design. The repeated-measures ANOVA was used to test the hypothesis for the quantitative data, and NVivo 12 was utilized to analyze the qualitative data. The participants' problem-solving skills were determined by their responses to items on RICOSRE-integrated worksheets. The students' responses were graded using a validated and reliable problem-solving rubric. The findings indicated that the students' problem-solving skills improved consistently in the upper, middle, and lower academic groups that were taught by implementing RICOSRE.