Assessment plays a crucial role in the learning process and significantly impacts students' understanding of tasks and their engagement. With the increasing popularity of e-learning, cognitive assessment methods are becoming more prevalent, and they can help develop students' high-order thinking skills (HOTS). Thinking-Aloud Peer Assessment (TAPA) is one such method that enables students to provide feedback on their peers' assignments while articulating their thinking processes. This study aims to investigate the impact of TAPA on HOTS in elementary school students. The four-week TAPA method was used to assess the students' math lessons in e-learning. Pre- and post-tests using the Ricketts Critical Thinking Questionnaire and Cassidy and Long Problem-Solving Questionnaire were conducted to measure the method's effect on the student's HOTS. The questionnaires' reliability was calculated using Cronbach's alpha coefficient, resulting in scores of 0.84 and 0.81, respectively. Data analysis involved an analysis of variance test, revealing a significant difference between the experimental and control groups in all questionnaire components. The results suggest that the TAPA method can positively impact the development of students' HOTS. Overall, the study highlights the potential of TAPA as a valuable tool for fostering HOTS. By addressing its limitations and building upon its strengths, educators can leverage this method to better equip students for their cognitive development in eLearning environments.