This study assessed suitable lettuce (Lactuca sativa L.) cultivars and lighting conditions for indoor hydroponic cultivation in Mongolia, examining their applicability in a household-scale vertical farming system. Three cultivars— ‘Jeokchima,’ ‘Cheongsangchu,’ and ‘Meiguodashusheng’— were grown under two lighting treatments: LEDs and T5 LEDs. ‘Jeokchima’ demonstrated the most consistent and superior growth across both harvests, exhibiting significantly higher leaf length, SPAD value, dry weight, and leaf number compared to the other cultivars. The use of LED lighting enhanced all growth parameters, except for petiole length, compared to T5, highlighting its advantages in arid indoor environments. Based on these findings, a compact three-tier Deep Water Culture (DWC) system was designed as a model for urban households, facilitating year-round lettuce production in limited indoor spaces. This model shows promise for enhancing vegetable self-sufficiency and food security in Mongolia. Further research on optimizing light spectra, managing photoperiods, and diversifying cultivars is recommended.