Social networking services (SNSs) are useful tools; however, problematic use leads to mental health problems. This study aimed to examine whether SNS addiction is associated with occupational dysfunction while considering the effects of depression. This cross-sectional study included 268 undergraduates who responded to the questionnaire on the frequency and time of SNS use, the Center for Epidemiologic Studies Depression Scale (CES-D), SNS-X scale, and the Classification and Assessment of Occupational Dysfunction (CAOD). Hierarchical multiple regression analysis showed effect of the SNS-X score for Instagram was significant (β = 0.174, p = .001) adjusted by the CES-D total score. However, the effect of frequency and time of SNS use were not significant. This suggests that SNS addiction, and not SNS use, is a factor associated with occupational dysfunction that should be emphasized and depression.