This quasi-experimental study was conducted to investigate the effects of the 4S Learning Cycle Model on students' reasoning skills. The participants of the study were the two intact classes of freshmen education students in College and Advanced Algebra course enrolled during the 1st semester SY 2019-2020 at the University of Science and Technology of Southern Philippines. One section was assigned as a control group who was exposed to Polya's Method of Problem Solving while the other one was an experimental group who was exposed to 4S (Sense-Making, Showing Representation, Solution and Explanation, and Synthesizing) Learning Model. It used open-ended questions to determine students' reasoning skills. The questions were selected based on the cognitive demands and the content involved corresponding with the structure of the reasoning ability. The problem tasks were assessed according to three problem-solving skills: reproduction, connection, and reflection. The performance of the students was measured using their test scores. To determine if the 4S Learning Model significantly affects the reasoning skills of the students, the Analysis of Covariance (ANCOVA) was utilized at a 0.05 level of significance. Results of the analysis revealed that the students exposed to 4S Learning Cycle Model have significantly higher reasoning skills compared to students exposed to Polya's Problem Solving Model. Based on these findings, it can be concluded that the 4S Learning Cycle Model is effective in enhancing students' reasoning skills.