IntroductionBoard games can be used as a playful educational practice in the teaching and learning process, as they constitute an educational technology that can be a source of health knowledge and an aid in decision-making. The objective of this research was to assess the effect of a board game on imprisoned women’s knowledge about STIs.MethodsA quasi-experimental study was conducted in 2022 with 64 imprisoned women who were students at a school located in a prison unit from the city of Recife, state of Pernambuco, Brazil. A 32-item instrument was used to assess knowledge about sexually transmitted infections before, immediately after the intervention and at 15 days. The intervention consisted in applying the Previna board game in a classroom. All the analyses were performed in the Stata software, version 16.0, with a 5% significance level.ResultsThe knowledge mean in the pre-test was 23.62 (± 3.23) points, whereas it rose to 27.93 (± 2,28) in the immediate post-test, dropping to 27.34 (± 2.37) (p < 0.001) in post-test 2, which was performed 15 days after the intervention. There was a statistically significant difference in the means obtained between the pre-test and the immediate post-test (p < 0.001), with a difference of 4.241 points, as well as between the pre-test and post-test 2 (p < 0.001), a difference of 3.846 spots.ConclusionsThe Previna board game significantly increased its players’ knowledge about STIs, and such increase in knowledge remained significant during the follow-up period.