This study explored whether factors, such as demographic characteristics, pre-college academic achievement (measured by self-reported high school grade point average), and college involvement have an influence on the postsecondary academic achievement of first-generation college students as measured by self-reported college grade point average. This study addressed first-generation college students who attend a four-year institution. This exploration used Astin's (1970; 1993) inputs-environments-outcomes model as a theoretical framework and utilized multiple regression for statistical analysis. The findings showed that the four blocks in the study explained approximately 12.4% of the variance of postsecondary academic achievement. Specifically, demographic characteristics and pre-college academic achievement explained the majority of the variance of postsecondary academic achievement. This study's findings cautiously offer practical implications for higher education administrators and researchers.