Halide perovskite multiple quantum wells (MQWs) have recently shown great potential in the field of light-emitting diodes. We report a facile solution-based approach to fabricate dimensionality-tunable perovskite MQWs by introducing 1-naphthylmethylammonium (NMA) cations into CsPbI₃ perovskites. Through the dimensional tailoring of (NMA)₂Cs_n–1Pb_nI_3n+1 perovskite MQWs, the crystallinity and photoluminescence quantum efficiencies (PLQEs) are significantly improved. We have obtained high-performance red perovskite light-emitting diodes (PeLEDs) with a luminance of 732 cd m^–2 and a maximum external quantum efficiency of 7.3%, which are among the best-performing red PeLEDs. Significantly, the maximum luminance of our PeLEDs is obtained at a low applied voltage of 3.4 V, with a turn-on voltage close to the perovskite band gap (V_turn-on ≈ 1.9 V). These outstanding performance characteristics demonstrate that dimensional tailoring of perovskite MQWs is a feasible and effective strategy to achieve high-performance PeLEDs, which is attractive for full-color display applications of perovskites.