This research aimed to adapt and validate a measuring scale of perceived research competencies among undergraduate students. Perceived research competencies of undergraduate learning can be measured with a new scale adapted from self-determination theory. We assessed the validity of this new measure applied to 307 participating undergraduates from Lima (Peru). The instrument’s survey items in the perceived competencies scale were first translated from English to Spanish and then adapted to focus on participation in research activities. We obtained evidence for (a) content validity (through item analysis), (b) internal structure with Mokken Scaling Analysis and structural equation modeling to examine the item–construct relationship, differential item functioning, and reliability, and (c) association with external variables. The items were found to function one-dimensionally, with strong item–construct relationships and no differential functioning (academic semester and general self-esteem groups). Theoretically consistent associations were found between study satisfaction and anxiety symptoms (controlling for gender, semester, and social support). We also discussed the theoretical implications and practices of this newly adapted measurement instrument.