The purpose of this study was to examine the effect of motivation on upper-grade elementary students' preferences for acoustic or tablet-based instruments. The effect of cultural familiarity on musical instrument preference was also investigated. Participants (N = 138) were classified by motivation levels (low, medium-low, medium-high, and high) and played the guitar, tablet-based guitar, gayageum (Korean string instrument), and tablet-based gayageum. After playing each instrument, participants rated preferences and provided their reasons. Results of the mixed-model ANOVA revealed two significant main effects for instrumental mode (acoustic vs. tablet-based) and motivation on instrument preference. A significant three-way interaction was also found: Cultural Familiarity × Mode × Motivation. The two main effects of mode and motivation produced a general pattern in instrument preference: (a) Students generally preferred acoustic instruments to tablet-based instruments, and (b) the level of motivation was associated with the degree of preference ratings. However, the interaction effect deviated from the general pattern; the low motivation group participants' preference ratings between acoustic and tablet-based guitars were not significantly different. This deviation from the general pattern appeared only for the culturally familiar instrument (guitar) but not the culturally unfamiliar instrument (gayageum) among the low motivation group.