This study mainly investigated (a) the relationship among grammar learning strategies, self-efficacy and learner autonomy and (b) their effects on academic success. Investigating all of them gives some clues for classroom practice. The study was conducted at Gaziantep University Foreign Languages Higher School with the participation of 350 students from four different proficiency levels (elementary, pre-intermediate, intermediate and upper-intermediate). The data were collected through a questionnaire that has three parts with 65-items. The data collected through the questionnaires were analyzed by means of the quantitative method including calculating descriptive statistics. According to analysis results, there is a positive relationship between grammar learning strategies and academic success (r=.185 p>.01), self-efficacy and academic success (r=.455 p>.01) and learner autonomy and academic success (r=.120 p>.01). When grammar learning strategies, self-efficacy and learner autonomy were investigated together, it was observed that there was a statistically positive relationship with academic success (r=.472 p>.01).