<![CDATA[Mathematics learning requires students to develop not only conceptual knowledge but also mathematical problem-solving skills and positive self-concept. However, junior high school students often experience difficulties in solving contextual problems, particularly those involving the Pythagorean Theorem. This study aimed to develop a Google Sites-assisted Problem-Based Learning (PBL) model to enhance junior high school students’ mathematical problem-solving skills and self-concept in learning the Pythagorean Theorem. This study employed a Research and Development (R&D) approach using the Borg and Gall development model, consisting of ten stages: research and information collecting, planning, preliminary product development, preliminary field testing, main product revision, main field testing, operational product revision, operational field testing, final product revision, and dissemination and implementation. The developed product integrated PBL syntax with Google Sites to provide contextual problems, digital learning resources, collaborative activities, worksheets, and assessments. Preliminary field testing involved 10 students, while the main and operational field testing involved 20 students. Data were collected through validation instruments, mathematical problem-solving tests, self-concept questionnaires, and student performance assessments. The results showed that the preliminary field trial produced an average self-concept score of 84%, categorized as high. In the revised operational trial, the experimental group obtained a mean score of 63, while the control group obtained 70.5. The effectiveness test produced a mean N-Gain score of 0.4603 or 46.03%, categorized as moderate. Thus, the developed Google Sites-assisted PBL model demonstrated sufficient effectiveness and potential as an alternative mathematics learning resource for supporting students’ learning outcomes, problem-solving skills, and positive self-concept.]]>
