The present study investigated which facets of perceived self-efficacy (PSE) in L2 reading are significantly related to L2 reading proficiency (L2RP), which type of linguistic knowledge feeds into PSE, and how they are related to L2RP when considered together. Participants (n = 95) were college students from two universities in Seoul. Four subcomponents of PSE were identified for investigation: text-based PSE, general PSE, PSE in linguistic knowledge, and PSE in authentic reading. The result of stepwise multiple regression analysis showed that the general PSE whose items reflect dimensions of social comparative influences and perceived controllability over environments was the only significant predictor of L2RP (R2 = 17.7%). For the relationships between linguistic knowledge and PSE, vocabulary knowledge (VK) was shown to be the only significant predictor of PSE when considered together with grammar knowledge (GK) and L2RP (R2 = 22.9%), while VK and GK were significant predictors of L2RP (R2 = 69.4%). PSE was not found to make an independent contribution to L2RP when considered with linguistic knowledge.