Background Early exposure to Computer Science (CS) and Computational Thinking (CT) for all is critical to broaden participation and promote equity in the field. But how does the introduction of CS and CT into primary school curricula impact learning, perception, and gaps between groups of students? Methodology We investigate a CS-curricular reform and teacher Professional Development (PD) programme from an equity standpoint by applying hierarchical regression and structural equation modelling on student learning and perception data from three studies with, respectively, 1384, 2433 and 1644 grade 3–6 students (ages 7–11) and their 83, 142 and 95 teachers. Results Regarding learning, exposure to CS instruction appears to contribute to closing the performance gap between low-achieving and high-achieving students, as well as pre-existing gender gaps. Despite a lack of direct influence of what was taught on student learning, there is no impact of teachers’ demographics or motivation on student learning, with teachers’ perception of the CS-PD positively influencing learning. Regarding perception, students perceive CS and its teaching tools (robotics, tablets) positively, and even more so when they perceive a role model close to them as doing CS. Nonetheless, gender differences exist all around with boys perceiving CS more positively than girls despite access to CS education. However, access to CS-education affects boys and girls differently: larger gender gaps are closing (namely those related to robotics), while smaller gaps are increasing (namely those related to CS and tablets). Conclusion This article highlights how a CS curricular reform impacts learning, perception, and equity and supports the importance of (i) early introductions to CS for all; (ii) preparing teachers to teach CS all the while removing the influence of teacher demographics and motivation on student outcomes; and (iii) having developmentally appropriate activities that signal to all groups of students.