Making connections between the representations of trigonometric functions and an interpretation of graphs of the functions are major challenges to many students. This study explores the effectiveness of the GeoGebra on grade 12 students' success in making connections between the representations of trigonometric functions and the interpretation of graphs. A nonequivalent control-group pre-test post-test quasi-experimental design was used. The sample of the study consisted of sixty-one grade 12 students from two schools. The results showed that there was a statistically significant difference between the mean achievements of the experimental group and the control group on making connections between representations of trigonometric functions, and on analyses and interpretations of representations of trigonometric functions, in favour of the experimental group. This study extends the findings of previous studies on the effectiveness of dynamic mathematics software on students' learning of representations and interpretation of graphs of trigonometric functions.