This study was conducted on six-year-old ‘Moneiby' pummelo trees grown at the experimental farm, Faculty of Agriculture, Kafrelsheikh University, Kafr El-Sheikh, Governorate, Egypt during the 2019 and 2020 seasons. The aim was to evaluate the effect of different levels of fertilization with nitrogen (N), phosphorus (P), potassium (K) and magnesium (Mg) on the vegetative growth, leaf mineral contents, yield and fruit quality of ‘Moneiby' pummelo trees. Nutrients were applied at the following five different levels: 60:15:60:1 (T₁), 85:20:80:1.25 (T₂), 105:25:100:1.5 (T₃), 125:30:120:1.75 (T₄) and 145:35:140:2 (T₅) unit/feddan/year, respectively. The obtained results indicate that fertilization with NPK and Mg at 125:30:120:1.75 and 145:35:140:2 unit/feddan/year (T₄ and T₅), respectively improved tree growth in terms of shoot length, diameter, leaf area, the annual increase of tree height, trunk circumference and canopy volume as well as leaf N, P, K, Ca, Mg, Fe, Mn and Zn contents during both seasons. Thereby, the best fruit set, and lowest June and preharvest fruit drops percentages were also achieved with both treatments. All treatments effectively improved fruit yield and quality compared to control during both seasons. Overall, the best results were achieved with T₄ under the clay soil conditions.