This research aimed to show the effect of a differentiated Turkish teaching program on the critical thinking skills of gifted students according to a parallel education program. In the research, a unique educational program was developed by differentiating the Turkish Language Arts lesson “Health and Environment” with a parallel education program. The study was conducted in Istanbul with 26 gifted (13 experimental and 13 control group) students in the fourth grade of a private school for gifted students. In the experimental group, the Turkish teaching program was differentiated according to the parallel curriculum program applied by the researcher, and the control group students continued their traditional course of study with their existing teachers. The Critical Thinking Ability Scale were administered to the experimental and control groups, and the data was subjected to statistical analysis with non-parametric statistical techniques. According to the findings of the research, the post-test results showed that the experimental group had significantly higher scores in critical thinking skills in relation to the Turkish Language Arts lesson.