The knowledge of Mathematics is germane to the scientific and technological development of nations all over the world. In addition to this, the integration of Information and Communication Technology (ICT) cum advances in pedagogy have made educators all over the world adopt innovative approaches that are ICT-inclined to enhance students’ acquisition of mathematical skills and also to enhance their academic achievement. In view of this, this study determined the effect of scratch programming language (SPL) on achievement in Geometry among senior secondary one (SS 1) students in Ibadan North Local Government Area of Oyo State, Nigeria. The study adopted the pretest-posttest control group quasi-experimental research design. The participants were 116 (75 males and 41 females) Senior Secondary School students in two intact classes from two public schools in Ibadan North Local Government Area. The instruments used for data collection were the Students Achievement Test in Geometry (SATG) (with a reliability coefficient of 0.75) and the Instructional Guide or Manual for the use of Scratch Programming Language (TGUSPL). Data were analyzed using Analysis of Covariance (ANCOVA). Results revealed that there was a significant main effect of treatment on students’ achievement in Geometry (F(1, 111) = 124.80; p<0.05, partial η2 = 0.53). Gender also had a significant main effect on students’ achievement in Geometry (F(1, 111) = 20.25; p<0.05, partial η2 = 0.15). It is, therefore, recommended that teachers and curriculum developers should adopt the use of Scratch programming language (SPL) for teaching Geometry for improved achievement in this aspect of Mathematics.