This study examined the relationship between personality traits and academic performance among Grade 11 students at Dolores National High School (DNHS). Using a correlational research design, data were collected from 287 students selected through stratified random sampling from a population of 1,010 learners. Personality traits were measured using an adapted Big Five Personality Inventory, while academic performance was based on students’ first semester general averages. Descriptive statistics and Pearson’s correlation analysis were employed to analyze the data. Results revealed that most students demonstrated moderate levels of conscientiousness, agreeableness, and openness to experience. In terms of academic performance, the majority obtained grades within the satisfactory range (85–89). Correlation analysis showed that conscientiousness had a strong positive and significant relationship with academic performance, while openness to experience and agreeableness showed moderate and weak but significant positive relationships, respectively. Extraversion and neuroticism were not significantly related to academic performance. The findings highlight the importance of fostering positive personality traits, particularly conscientiousness and openness, to enhance students’ academic success in a public senior high school context.