The present article investigates the effects of epistemic beliefs (i.e. beliefs about the nature of knowledge and knowing) on the effectiveness of information literacy instruction (i.e. instruction on how to search for scholarly information in academic settings). We expected psychology students with less sophisticated beliefs (especially multiplicistic students viewing psychological knowledge as inherently subjective) not to recognize the value of differentiated information searches and of the respective instructional courses. In a first intervention study with 67 psychology students, multiplicism was shown to reduce information-seeking skills students gain throughout the intervention. In a second intervention study with 64 psychology students, students with higher multiplicistic beliefs subjectively benefited less from the information searches carried out during instruction (in terms of reduced increases in subjective topic-specific knowledge). In conclusion, we recommend including elements from epistemic belief instruction into information literacy instruction.