The purpose of this study was to study how L2 motivations in both Dörnyei’s (2005, 2009) L2 Motivational Self System and Gardner’s (1985) socio-educational model were related to intrinsic and extrinsic subscales in the self-determination theory (Deci & Ryan, 1985) in Korean college contexts. This study investigated the relationships among the motivational variables by the use of the correlation method and the effects of L2 motivations on motivated behavior through multiple regression analysis. The findings showed Gardner’s (1985) integrativeness and ideal L2 self were strongly correlated with the more self-determined types of motivations, while L2 learning experience and ought-to L2 self were associated with the less self-determined ones in the self-determination theory. In addition, Dörnyei’s (2005, 2009) L2 Motivational Self System and the extrinsic motivation subscales, identified regulation and external regulation, explained Korean college students’ motivated behavior better than Gardner’s (1985) integrativeness. The theoretic discussions are made at the conclusion.