Abstract <p>The response to foliar application of Gromor nano diammonium phosphate (nDAP) on growth, physiology, yield and quality of Okra (<i>Abelmoschus esculentus</i>) was evaluated under open field conditions. Field experiments were carried out during Summer and <i>Kharif</i> seasons of 2024 with ten treatments comprising soil application of P (50, 75, 100% recommended dose of phosphorus (RDP) in combination with nDAP (no spray, one spray and two sprays) along with a control, replicated four times in a randomized block design (RBD). Plants received 75% RDP + two rounds of nDAP foliar spray exhibited a notable increase in plant height (71.8 cm) and leaf area (625 cm²). The same treatment (T₆) exhibited significantly higher photosynthetic rates (31.2 µmol CO₂/m² s), stomatal conductance (0.64 mol/m² s), quantum yield (0.68 <i>F</i>_v/<i>F</i>_m ratio) and water use efficiency (4.59 µmol CO₂ mm H₂O) compared to (T₁₀) 100% RDP with no nDAP spray which recorded 27.4 µmol CO₂/m² s, 0.50 mol/m² s, 0.64 <i>F</i>_v/<i>F</i>_m ratio and 3.64 µmol CO₂ mm H₂O, respectively. Consequently, plants sprayed with nDAP had higher photosynthetic activities, growth and expanded leaf area facilitated the plants to produce 31 t/ha fruit yield while 100% RDP had only 19.9 t/ha which is higher by 43.1% with a saving of 25% RDP. Further, the nDAP sprayed okra plants produced fruits with higher carbohydrates and ascorbic acid while low crude fibre indicating tenderness than 100% RDP. Nutrient uptake and phosphorus use efficiency was higher in the nDAP sprayed okra plants. The data clearly demonstrated that the nDAP assists in improved growth and physiological changes which collectively contributed to the increased fruit yield and enhanced fruit quality.</p>