Efforts are being made to add Computational Thinking (CT) to the curriculum of primary schools in order to develop student abilities to use computational tools to solve problems and better prepare them for an increasingly digital society. Distributed Practice (DP) and Retrieval Practice (RP) are evidence-based practices that have shown to lead to efficient and durable learning. Studies investigating Distributed Retrieval Practice (DRP), a combination of the two evidence-based practices, have found positive effects of DRP on university student learning of anatomy and vocabulary items. As CT is considered to be a complex thinking skill, one that is acquired over time with practice, we investigated whether DRP had durable effects on primary student learning of CT concepts. We conducted a quasi-experimental study involving 20 primary school students between 11 and 12 years of age. The students participated in 6 weekly sessions on CT and completed two tests -- one at the end of the fifth session (immediate) and the other a week later (delayed). At the end of each of the first 4 sessions, students performed DRP by completing a class-wide review quiz consisting of 5 multiple-choice questions. The results of the study show that students attained higher scores on the delayed test (72.6% ± 19.2) in comparison to the immediate test (67.9% ± 20.7). However, the difference in scores was not significant. The results suggest that DRP may play a role in helping students overcome the natural decay of memory, however, studies with a larger sample size are required. Further, this study demonstrates that DRP can be applied in an authentic classroom environment that involves primary school student learning of a complex subject such as CT.