This study aimed to examine the level of knowledge, attitudes, and use behavior of emergency contraceptive pills, and to determine factors associated with the knowledge and acceptance of emergency contraceptive pill. The sample group in this study included 465 students in 4 government and private vocational schools in Phutthalung province. A self-administered questionnaire was used as an instrument for data collection. Statistical analyses used were percentage, mean, standard deviation, c2 test, and Multiple Regression Analysis The sample group comprised 48% females and 52% males, aged between 14 - 24 years. About 33% (40% males and 27% female) had sexual experience. Only 34% had received information on emergency contraceptive pills. The major source of information was from friends. The majority had a low level of knowledge about emergency contraceptive pills. Only 9% knew the correct timing of using emergency contraceptive pills. Their level of attitude towards emergency contraceptive pill ranged between moderate to high level. It is noted that 14% of the sample students still had the misconception about emergency contraceptive pills that it is against ethical values since it might cause an abortion. However, about 21% of those who had sexual experience had used emergency contraceptive pills. The result of analysis on factors associated with the knowledge on emergency contraceptive pill suggested that females had less knowledge about the pill than males. The samples with knowledge of sex education and contraception and who had received information about the pill from medical personnel had positive associations with the knowledge on emergency contraceptive pills. Moreover, males were more likely to accept emergency contraceptive pills than females. The older adolescents with knowledge of how to use the pill and its effect, and having knowledge of sex education and contraception were more likely to accept emergency contraceptive pills. The result pointed out that about half of the sample students lacked knowledge about risk opportunity of pregnancy, and used emergency contraceptive pills incorrectly. This group had experienced failure in using emergency contraceptive pills but still planned to continue using it. One practical means to solve this problem is providing sex education and accurate knowledge in family planning and birth control as well as suggesting effective methods to this particular group so that they would have correct knowledge and become more confident to use emergency contraceptive pill correctly, however, as an alternative method only in case of emergency.