Background: Engineering education and other discipline-based education researchers may motivate their work with claims that STEM (science, technology, engineering, and mathematics) norms and culture are unique, thus requiring focused study. As research on disabled students gains momentum in engineering education, it is important to understand differences that limit generalizability of prior work in other disciplines to STEM. Purpose: What do studies document as differences between STEM and non-STEM settings that impact disabled undergraduates, and to what extent are these studies using asset-based perspectives of disability? Scope/Method: This systematic review identified US studies that compared STEM to non-STEM disciplines in regards to disabled undergraduate students. The qualifying studies, published during 1979-2023, comprise 22 journal articles and 15 doctoral or master's theses. Most studies used quantitative methods (n = 28). Results: Of the 37 qualifying studies, 20 instructor studies provided moderate evidence that STEM instructors are less willing or less knowledgeable about how to support disabled students through accommodations or course design. We highlight a small number of student studies identifying assets of disabled students, although most took a deficit view by comparing disabled student experiences to an able-bodied norm. Few studies emphasized the structural characteristics of STEM such as culture and educational practices that contribute to socially constructing disability by acting as barriers that disable students. Conclusions: More work is needed to examine instructor actions beyond their intentions and attitudes toward disabled students. Critical and asset-based perspectives are needed in future study designs that center disability to uncover systemic barriers and identify assets disabled students bring to STEM.