In this article, we present the impact evaluation of Irûmi, an educational robot-based intervention aimed at developing second-grade students' computational thinking (CT) skills in Paraguay. Our results indicate that the program had an effect of 0.09 standard deviations on the students' CT skills, focusing on abilities such as abstraction, algorithmic thinking, and evaluation. These findings suggest that with age-appropriate instructional design, very young children could develop CT skills and, that smart devices and electronic toys can contribute to their development at early ages. Our study contributes to the empirical literature because it is applied to a developing country, uses an experimental design, pre-and post-treatment measures, and a large student sample, and explores the programs impact on students and teachers. In addition to the impact on students CT skills, we found that Irûmi had effects on other dimensions for which it may not have been intentionally designed. First, our results suggest that Irûmi raised preferences towards Science, Technology, Engineering, and Mathematics (STEM) toys and increased gender flexibility toward who can play with them, especially among girls. Second, the program increased children's positive attitudes toward technology. The mechanisms by which the effects of Irûmi occur are several. First, the program increased the probability that the teacher would use educational technology in the classroom, including devices not contemplated by the program. Second, we found that Irûmi developed teachers CT skills, possibly due to the novelty of the curriculum and methodology in the Paraguayan context.