Critical thinking skills are high-level thinking skills that support intellectual curiosity and give birth to answers that are creative and open. The industrial era of the 21st century 4.0 places great emphasis on critical thinking skills that make it easy for students to deal with a variety of problems. This study aims to design teaching materials in the form of student worksheets that contain activities in accordance with the steps of the problem-based learning model and indicators of critical thinking skills with the ultimate goal of increasing critical thinking skills. This study uses the ADDIE development method with five stages, namely: (1) Analysis, (2) Design, (3) Development, (4) implementation and (5) evaluation. The limit of this research is to analyze and design, the subjects in this study were students of class VII IT Luqman Al-Hakim International Yogyakarta. Data collection instruments include observation sheets, interview guidelines, and validation sheets. The results of the study concluded that the PBL-based student worksheets design to improve critical thinking skills was developed through the ADDIE development method with components: cover pages, preface, table of contents, concept maps, Core Competencies, basic competencies, basic indicators, student worksheets activities, evaluations, and summaries. Student worksheet has been validated by two validators and is categorized as feasible with some revisions that researchers have fixed. This research can be continued at the development and implementation stages.