The purpose of this study was to investigate the effects of vocabulary learning activity types via smart-phones on vocabulary learning and the attitude of Korean college students. The participants were 56 college students, who were divided into 4 groups: a competitive and self-paced group (Group 1), a competitive and controlled-paced group (Group 2), an individual and self-paced group (Group 3), and an individual and controlled-paced group (Group 4). Vocabulary tests were administered before and after the experiment. The analyses of the post-test results showed that Group 3 had improved most and Group 1 earned the second highest score, indicating that competition can make a positive effect on vocabulary learning via smart-phone applications. The results also revealed that there was no statistically significant difference in the post-test scores between self-paced and controlled-paced groups. In addition, vocabulary learning via smart-phone applications improved the participants’ attitudes toward vocabulary learning.