While alignment in laughter production has been shown in adults, its presence in children remains understudied. We examined laughter responsiveness and acoustic alignment in middle childhood, comparing parent-child and parent-adult computermediated conversations. While no significant differences were found in laughter frequency, antiphonal laughter was less frequent in parent-child interactions, despite intra-dyadic balance. Acoustic analysis revealed an increase in low-frequency spectral modulations in antiphonal laughter. To test whether this was due to local alignment with the preceding laughter, we compared distances from genuine and pseudo-random initiatingantiphonal laughter pairs. In parent-adult interactions, genuine laughter pairs exhibited greater acoustic similarity than pseudorandom pairs, a pattern absent in parent-child interactions. Our study contributes to discussions on alignment theories and the role of laughter in pragmatic development.