Shallot (Allium cepa var. Aggregatum) is one of the leading horticultural commodities in Indonesia. Improving the productivity of shallots grown from True Shallot Seed (TSS) can be achieved through appropriate fertilizer combinations and optimum plant population. This study aimed to determine the effect of combinations of NPK fertilizer and Azolla liquid organic fertilizer (LOF) at different plant populations on the growth and yield of TSS shallots. The experiment was conducted in Ngringo Village, Jaten District, Karanganyar Regency, Indonesia, from October 2025 to January 2026 using a split-plot Completely Randomized Design (CRD). The main plot consisted of 100% NPK, 75% NPK + 100% Azolla LOF, and 50% NPK + 100% Azolla LOF, while the subplot consisted of planting spacings of 20 × 20 cm, 20 × 10 cm, and 10 × 10 cm. Data were analyzed using analysis of variance (ANOVA) followed by Duncan's Multiple Range Test (DMRT) at the 5% significance level. The interaction between fertilizer combinations and planting spacing significantly affected plant height, number of leaves, and number of bulbs per clump. The combination of 75% NPK + 100% Azolla LOF produced the highest number of leaves and bulbs per clump, whereas the 10 × 10 cm spacing produced the highest yield of 16.80 t ha⁻¹. These findings indicate that the combination of 75% NPK and 100% Azolla LOF has the potential to reduce inorganic fertilizer use while supporting the growth of TSS shallots.