This study aimed to examine the effect of the Reading, Identifying, Constructing, Solving, Reviewing, and Extending (RICOSRE) learning model assisted by Mind Mapping on the critical thinking skills of Grade 10 Biology students. A quantitative quasi-experimental design featuring a non-equivalent pretest-posttest control group design with intact classes was implemented. The study population comprised 112 Grade 10 Science students across four classes at SMAN Bhakti Mulya Bunga Mayang during the 2026/2027 academic year. Using cluster random sampling, two intact classes were selected: Class X.3 (n = 28) served as the experimental group (taught via Mind Mapping-assisted RICOSRE), while Class X.2 (n = 28) served as the control group (taught via conventional Discovery Learning). Data were collected using a validated 10-item essay test measuring five critical thinking indicators adapted from Ennis. Analysis of normalized gain (N-Gain) scores revealed that the experimental group achieved a mean posttest score of 81.21 ± 8.42 with a high average N-Gain of 0.70, whereas the control group obtained a mean posttest score of 62.64 ± 9.15 with a moderate N-Gain of 0.43. Because the posttest data violated normality and homogeneity assumptions, hypothesis testing was performed using the non-parametric Mann-Whitney U test on posttest scores. The test yielded U = 0.50, z = -6.45, p < .001, indicating a statistically significant difference between the two groups. These findings suggest that integrating Mind Mapping specifically during the Constructing syntax of RICOSRE offers a structured visual scaffolding that facilitates students' analytical and evaluative skills in ecosystem topics.