This study investigated the effect of study habits on academic achievement in Financial Accounting among Senior Secondary School II (SS2) students in Aba Education Zone, Abia State, Nigeria. The research specifically examined the role of personal (psychological) factors and peer group influence as sub-variables of study habits. The study adopted a correlational research design to determine the relationship between the independent variables and students’ academic performance in Financial Accounting. A total of 250 students were selected from public and private secondary schools in Aba Education Zone using a stratified random sampling technique to ensure representativeness. Data were collected using a structured questionnaire on a four-point Likert scale and analyzed using descriptive statistics (mean, standard deviation) and inferential statistics (multiple regression analysis). The findings revealed that personal (psychological) factors, including motivation, self-efficacy, and attitude, had a significant positive effect on students’ academic achievement in Financial Accounting. Similarly, peer group influence was found to significantly affect students’ performance, indicating that positive peer interactions, collaborative learning, and academic encouragement enhance learning outcomes. Descriptive analysis further showed that respondents generally exhibited moderately high study habits, which contributed to their performance in Financial Accounting. Based on these findings, the study concluded that both internal factors (psychological) and external factors (peer-related) are crucial determinants of students’ academic success. The study recommends that students develop effective study routines, teachers promote collaborative learning, and parents and school administrators support positive peer interactions and motivational initiatives. It is further recommended that similar studies be conducted in other educational zones to generalize findings and explore additional variables that influence academic performance. This study contributes to educational research by highlighting the interplay between study habits, psychological factors, peer influence, and academic achievement, emphasizing the need for holistic approaches to improving students’ performance in Financial Accounting.