A qualitative study was conducted in a secondary school to evaluate student learning processes and outcomes by examining their inquiry questions, journals, and maker artifacts in a curriculum-based maker learning environment supported by the Guided Inquiry Design (GID). Thirteen 8th-grade students in a suburban middle school in the southwest of the United States participated in the study. Inquiry questions, maker artifacts, and inquiry journals were collected and analyzed with rubrics that were developed based on a critical review of literature drawn from different bodies of literature. The objectives of this study were three-fold: (1) evaluate the quality of students' inquiry questions and maker artifacts, (2) assess students' internal knowledge representation (IKR) and external knowledge representation (EKR), and (3) develop a robust and valid assessment framework for maker learning considering students' expertise development over time. The findings revealed that the students progressed at different developmental levels; therefore, expertise development should be incorporated into the assessment framework for maker learning. This study also implied that scaffolding should be tailored to meet special needs of each student in a maker learning environment. The originality of this research is that the assessment framework takes into account individuals' development and progress towards expertise over time, instead of focusing on their learning outcomes at a specific time point. An additional value of this study is that the tools and supporting materials that serve as instructional scaffolds also serve as tools to collect evidence about student learning performance, processes, and outcomes.