The use of dynamic geometry computer software (DGCS) is important in educational environment, and it is more advantageous for learning mathematics comprehensively. This study examined the importance of dynamic geometry computer software on learners' performance in geometry. A quasi experimental, non-equivalent control group was used. The instrument used in this study was geometry achievement mathematics test (GMAT) that comprised 15 multiple choices items. The GMAT was administered to 87 grade nine learners in two secondary schools in Tshwane south district, Gauteng Province South Africa. One school was used as experimental group and the second school was used as the control group. Data analysis employed the use of the statistical t-test independent sample. The result of the study shows that using DGCS is important in geometry whereby it improves the performance of learners. In addition, the results show that the software affects the female learners' mathematics performances more positively than the male learners. Hence, the results of this study showed that there is great potential in using the DGCS (GeoGebra) to teach secondary schools mathematics. The study recommends that the use of technology in teaching and learning of mathematics should be a priority in the schools.