The purpose of this study was to investigate the relationship between private lessons and academic achievement among students in grades 9 to 12 in Oman." The descriptive methodology was used, and the research tool was a questionnaire. A total of 4,500 male and female students were given the questionnaire. The investigation produced the following findings: Students in grades 9 to 12 in the Sultanate of Oman had a moderate view of the impact of private lessons on their academic performance, with an average score of 3.22. The items' average scores ranged from 2.45 to 4.32, showing a range of low to very high levels. The findings also revealed that the average score of basic education pupils in the Sultanate of Oman regarding the influence of private lessons on them was higher than the hypothetical mean. This difference was statistically significant at a significance level of less than 0.05, indicating that private courses had a clear and positive impact on students. The effect size was also estimated and found to be 0.778, indicating a medium effect size. The results of the regression analysis revealed no statistically significant relationship, at a probability value of less than 0.05, between students' perceptions of the impact of private lessons on them and their academic achievement, or belief in the effectiveness of private lessons in assisting students. The correlation coefficient was 0.045, indicating a very poor association, Furthermore, their perceptions of the influence of private lessons on them account for only 0.2% of the variation in academic accomplishment and belief in the usefulness of private lessons in supporting students. The coefficient of determination (R-squared) was found to be 0.002, indicating an exceedingly weak proportion and making findings unreliable. This underscores the assumption that students' impressions of the influence of private lessons on academic achievement or belief in the usefulness of private lessons in supporting students cannot be accurately predicted.