Balanced diet in the early stages of life plays a role in optimum growth and maintains good health status of adolescents. Dietary habits that are established during adolescence will sustain till adulthood. Therefore, this present study aims to identify the dietary patterns and to determine factors associated with dietary patterns in terms of socio-demographic characteristics, locality of schools, ethnicity, eating habits, self-perceived weight status, and food label reading habit among adolescents in Malaysia. Data from the Adolescent Nutrition Survey (ANS) 2017 was used for the present study. ANS is a population representative school-based cross-sectional study among school-going adolescents from primary four to secondary five from schools in 13 states and three federal territories registered under the Ministry of Education Malaysia. A self-administrated questionnaire was used to collect information on socio-demographic characteristics, locality of schools, ethnicity, eating habits, self-perceived weight status, and food label reading habit. A pre-tested face-to-face food frequency questionnaire (FFQ) was used to collect information on food group intake frequency. Dietary patterns were identified by using exploratory factor analysis and associated factors, using complex sample general linear model (GLM) analysis. All statistical analyses were carried out at 95% confidence interval or p-value < 0.05. The dietary patterns identified are healthy, unhealthy, and alternative proteins. The healthy dietary pattern was significantly associated with the types of school and ethnicity. The unhealthy dietary pattern was significantly associated with the locality of schools, ethnicity, frequency of snacks intake per week, frequency of eating out per week, self-perceived weight status, and food label reading habit. Significant associations were found between alternative proteins dietary pattern and locality of schools, ethnicity, and types of school. This study found that there is a disparity of dietary patterns between different ethnicity, locality of schools, and types of school. We recommend strategies of specifying ethnicity and geographical area to improve dietary patterns of adolescents in Malaysia.