Educational digital games are games designed for educational purposes. These games are used to provide students with certain knowledge, and designated with a with a view to improving their skills or to shaping their behavior. The aim of this study is to determine the effect of educational digital games Wordwall and Matific used in teaching primary school mathematics course on student achievement and attitude. Pre-test and post-test were applied to the experimental and control groups of the study in which quasi-experimental method was used. The study group consisted of 48 students studying in the 3rd grade of a public primary school. In the experimental group of the study, educational digital games Wordwall and Matific were used in the measurement unit of the mathematics course (length, perimeter, area, and liquid measurement). In the control group, the same subject was presented in accordance with the instructions in the third grade mathematics teacher's guide provided by Republic of Türkiye Ministry of National Education. The data were collected with the 20-question "Mathematics Achievement Test", which was jointly determined by the classroom teachers and the researchers, and the "Mathematics Course Attitude Scale" consisting of 13 items developed by Ayvaz (2010). In the analysis of the data, t-test for independent and dependent groups, which is one of the parametric tests appropriate to the research hypotheses, was applied. The findings of the study show the effectiveness of educational digital games in affecting students' academic achievement and attitudes. Based on this result, it is recommended that teachers should benefit from trainings in order to use educational digital games effectively in lessons.