Objectives: This study examined the effect of two different dance curriculums on executive functions and motor competence in 6–7 years old primary-school children across an 8-week period. One dance curriculum was underscored by creativity and the other was based on a choreographed dancing curriculum with high cognitive challenge. Design: Randomised-controlled trial. Methods: Sixty-two primary-school children (6.6 ± 0.5 years old; 47% females) participated for a control period in the regular school PE lessons, after which they were randomly assigned to two experimental groups – choreography dance group or creative dance group. The two experimental groups practiced dance for 8 weeks, twice a week, learning either a choreographed dance sequence with high cognitive challenge or creating their own dance sequence in a creative dance curriculum. Executive functions (working memory capacity, inhibition, and flexibility) and motor competence were assessed at three time points – baseline, pre-intervention and post-intervention. Results: There was a time effect for inhibitory control (p < 0.01), with a high improvement during the intervention (d = 0.76) than baseline (d = 0.46); for working memory capacity (p < 0.01), with a higher improvement during intervention (d = 0.43) than baseline (d = 0.31) in the high challenging task; and for motor competence (p < 0.01), with a higher improvement during baseline (d = 1.7) than intervention (d = 0.75); no other significant effects. Group differences revealed weak evidence that the choreography group improved inhibitory control and working memory more than the creative dance group. However, a check for pedagogy fidelity revealed that the creative-dance curriculum was not adopted as planned (i.e., high volume of teacher's instruction and small use of music). Conclusions: An 8-week dance intervention improved inhibitory control and potentially working memory capacity in grade one and two primary-school children. Contrary to prediction, the dance intervention did not improve motor competence beyond typical development. Discrepancy between the planned and adopted creative-dance curriculum suggests caution in interpreting results. This study provides new insights into the exercise-cognition relationship.