The authors' purpose was to investigate the effect of origami-based instruction on elementary students' spatial ability. The students' self-reported perceptions related to the origami-based instruction were also examined. Data was collected via purposive sampling techniques from students enrolled in a private elementary school. A spatial ability test (SAT) was used to measure the students' ability in mentally manipulating objects and their parts in 2- and 3-dimensional spaces. In addition to the SAT, reflection papers and interviews were used. The results indicated that origami-based instruction had a positive effect on the students' spatial ability scores. The data analysis showed that the students developed positive opinions about origami-based instruction and its relation to mathematics; however, they experienced difficulties when folding the paper.