Chili plant growth and yield are heavily determined by soil fertility, which is in turn influenced by the quantity or dosage of fertilizer applied. This study aimed to evaluate the growth and yield of 'Mahkota' chili plants grown in media supplemented with varying dosages of NPK booster fertilizer. The experiment employed a Randomized Block Design (RBD) with NPK booster dosages of 0 g, 5 g, 10 g, 15 g, 20 g, 25 g, and 30 g per polybag as the treatments. Each treatment was replicated three times, resulting in a total of 21 experimental units. Observed variables included plant height, number of branches, age at flowering, number of fruits, fruit length and diameter, and fresh fruit weight. The collected data were subjected to analysis of variance (ANOVA) to determine the effects of the treatments. Results showing significant or highly significant effects were further analyzed using the Honestly Significant Difference (HSD) test at the 5% level to compare mean values among treatments. The study results indicate that NPK booster dosage affects both the growth and yield of 'Mahkota' chili plants. A dosage of 30 g per polybag was more suitable for supporting vegetative growth, yielding the tallest plants (average 26.70 cm at 5 weeks after planting/WAP) and the highest number of branches (average 9.33 branches at 35 days after planting/DAP). Conversely, a dosage of 15 g per polybag was more effective for maximizing yield, resulting in the earliest flowering (36.33 DAP), the highest number of fruits (24.00 fruits/plant at 75 DAP), the greatest fruit length (8.54 cm), the largest fruit diameter (5.47 mm), and the heaviest fresh fruit weight (51.67 g/plant at 75 DAP).