The population of the study consists of primary school teachers working in the province of Eskisehir. The sample of the study consists of 321 primary school teachers working at 40 primary schools. In the present study, a questionnaire, an instrument to collect data, was used to determine teachers' perceptions of efficacy about individualized instruction. Frequencies and percentage were calculated in the analysis of the data. Results of the study indicated that primary school teachers perceived themselves as sufficient in terms of determining the aims and teaching activities. Furthermore, teachers perceived themselves moderately sufficient in terms of presenting different activities in scheduling; applying knowledge with property of students in scheduling to teaching-learning process and designing suitable teaching material in teaching-learning process; constructing the environment which helps students to realize their powerful and weak aspects. On the other hand, teachers perceived themselves insufficient in terms of scheduling teaching-learning process with convenient individual differences and constructing environment with convenient for students who need special education.