The 14-3-3 (GRF) protein family, a class of highly conserved regulatory proteins, plays a crucial role in plant responses to abiotic stresses. However, whether and how arbuscular mycorrhizal (AM) fungi mediate the entire 14-3-3 gene family to enhance drought tolerance in woody fruit crops remains unclear. This study aimed to investigate the effects of inoculation with Funneliformis mosseae on growth, photosynthesis, leaf relative water content, soluble sugars, hormones, antioxidant enzyme activities, and the expression of all 15 PtGRF family members in leaves of potted trifoliate orange (Poncirus trifoliata) under drought stress. Inoculation with F. mosseae significantly alleviated drought-induced growth inhibition in trifoliate orange. Under drought stress, AM fungal colonization enhanced plant biomass, leaf relative water content, and photosynthetic efficiency, and promoted the accumulation of sucrose, fructose, and glucose. Concurrently, AM fungi boosted the activities of superoxide dismutase, peroxidase, and catalase, and increased abscisic acid (ABA), trans-zeatin, isopentenyladenine, and indole-3-butyric acid levels, while reducing malondialdehyde and indole-3-acetic acid levels, thereby strengthening antioxidant defense and reprogramming hormonal balance. Drought stress generally suppressed the expression of most PtGRF family members. In contrast, AM inoculation reversed this trend and induced a condition-dependent expression pattern: under well-watered conditions, it up-regulated PtGRF1/2/6/10/12/13/15; under drought stress, it specifically induced PtGRF1/2/6/7/8/12/13/14. Crucially, correlation and principal component analyses further revealed a functional divergence among PtGRF members. PtGRF1/6/13 were closely linked to growth maintenance and antioxidant capacity, while PtGRF2/7/12/14 were strongly associated with sugar metabolism and stress signaling (positively correlated with sugars and ABA). In conclusion, the functional specialization of PtGRF members under mycorrhization serves as a regulatory hub, coordinating growth adaptation and metabolic reorganization, thereby synergistically improving host drought tolerance. Our findings establish a framework for understanding how a symbiotic microbe reprograms a host's gene family to create a multi-functional regulatory network for stress adaptation.