Social maturity refers to an individual's ability to adjust effectively with society, handle interpersonal relationships, and take responsibility for one's own actions and decisions. College life places new demands on students, who must simultaneously manage academic responsibilities, peer relationships and independent living, all of which call for a well-developed sense of social maturity. This study examines the impact of social maturity on the academic achievement of college students in Tirunelveli District. A sample of 200 college students was selected using simple random sampling from arts and science colleges across the district. Data were collected using a standardized Social Maturity Scale, while academic achievement was measured through the students' previous semester examination marks. Percentage analysis was used to describe the demographic and social maturity profile of the respondents, and One-Way ANOVA was applied to test the significance of differences across groups. The findings reveal that a majority of the students possess an average level of social maturity, that gender and locality significantly influence social maturity, and that social maturity has a statistically significant impact on academic achievement. The study recommends that colleges introduce structured life-skills and social-adjustment training to strengthen students' holistic development and academic performance.