Purpose: This study aims to investigate university students' knowledge about and attitudes toward e-cigarette (EC) use. It will also examine whether students' EC use is associated with knowledge about and attitudes toward EC use. The study also aims to analyze the determinants of students' use of ECs. The effects of gender, smoking behavior and friends' and family members' smoking behaviors on students' use of ECs were analyzed. Design/methodology/approach: Completed questionnaire surveys were received from 1,362 students at King Mongkut's University of Technology Thonburi in Bangkok City, Thailand, in November and December 2019. Chi-square tests and an independent samples t-test were conducted to determine whether students' knowledge about ECs and attitudes toward EC use influenced their use of ECs. A logistic regression analysis was performed to identify significant factors affecting students' use of ECs. Findings: The results revealed that students' EC use was associated with knowledge about ECs: Students with less knowledge about the harmful effects of ECs were more likely to use them. In addition, students who were EC users had more positive attitudes toward EC use than those who were not EC users. The results also revealed that male students, students who had also smoked tobacco cigarettes and students with friends who smoked tobacco cigarettes were more likely to use ECs. These results could suggest strategies to reduce the use of ECs among university students. Originality/value: This study provides deep understanding about university students' knowledge about and attitudes toward EC use and their participation in EC use. The result clearly shows university students who are participating in EC use still have less knowledge about EC, thus, they have positive attitudes toward ECs. Gaining social acceptance from friends who use EC also influences students' decision to use EC. Therefore, EC use among students could significantly increase overall EC use.