Objectives: This study aimed to investigate the effects of perceived behavioral control and alcohol identity on alcohol consumption in social drinking and solitary drinking, respectively. Methods: A survey was conducted with 521 Korean adults who had an experience of drinking alone. The amounts of alcohol consumption when drinking in a group and alone, perceived behavioral control, and alcohol identity were measured. Results: Results of the regression analyses are as follows. Both perceived behavioral control and alcohol identity had main effects on alcohol consumption when drinking both in a group and alone. There were also interaction effects of perceived behavioral control and alcohol identity. When people had a strong alcohol identity, the effects of perceived behavioral control on both drinking in a group and alone were stronger. Conclusion: These findings suggest that alcohol identity and perceived behavioral control should be considered when an intervention is designed to reduce alcohol consumption.