Objective To compare the effects of maxillary skeletal expansion (MSE) and traditional rapid maxillary expansion (RME) on nasolabiomental soft-tissue aesthetics in adolescents with maxillary transverse deficiency. Methods A total of 60 adolescent patients with maxillary transverse deficiency treated at Shanghai Taikang ByBo Songyao Dental Hospital from January 2024 to June 2025 were selected, and they were divided into the control group and the study group by the random number table method, with 30 patients in each group. The control group received RME treatment, and the study group received MSE treatment. The nasolabiomental soft-tissue aesthetic indicators [nasolabial angle (NLA), columella-labial angle (CMLA), upper-lip protrusion (ULP), labiomental angle (LLA), Z-angle, soft-tissue facial convexity angle (G-Sn-Pg′)], dental arch width, and expansion effect (skeletal expansion efficiency, molar buccal inclination) were compared between the two groups. Results After treatment, the NLA and CMLA in the study group were larger than those in the control group, and the ULP was smaller than that in the control group (P <0.05). There were no significant differences in LLA, Z-angle and G-Sn-Pg′ between the two groups (P >0.05). After treatment, the width of maxillary and mandibular dental arch in the study group was higher than that in the control group (P <0.05). The skeletal expansion efficiency in the study group was higher than that in the control group, and the molar buccal inclination was lower than that in the control group (P <0.05). Conclusion Both MSE and RME can improve nasolabiomental soft-tissue aesthetics in adolescents with maxillary transverse deficiency, whereas MSE shows superior performance in nasal aesthetic improvement and reduction of upper-lip protrusion.