There are many factors that affect academic achievement among first year college students in Saudi Arabia. The aim of this study was to improve our understanding of academic achievement of first year college students in Saudi Arabia by investigating the relationship between a selection of demographic, academic, and psychological variables and their effects on first-year students’ GPA. All first-year students admitted to the King Saud University in fall 2016 or spring 2017 were invited to complete a self-report survey. 1457 students have completed and submitted the survey. Multiple regression analysis was performed with all independent variables in order to determine whether there were any significant relations between the independent variables and academic achievement. Among the study variables, six variables predicted first-year students’ GPA. Those variables were high school, Saudi aptitude test, Saudi achievement test, gender, stress, and mother’s education level.