This study investigated the efficacy of edible gum arabic (GA) and carboxymethyl cellulose (CMC) containing moringa (M) leaf extract as postharvest treatments for maintaining organoleptic quality and controlling Colletotrichum gloeosporioides on ‘Maluma’ avocado fruit. For the quality study, after the fruit was dipped into the treatments: GA 10%, GA 15%, GA 10% + M, GA 15% + M, and CMC 1% + M and uncoated fruit served as control, the fruit were then stored at 5.5 °C [95% relative humidity (RH)] for 21 days, and moved to ambient conditions at 21 ± 1 °C (60% RH) for 7 days to simulate retail condition. Quality parameters that were evaluated include mass loss, firmness, and color changes (L*, a*, b*, respectively), and sensory quality attributes, such as taste, color, mouthfeel, odor, and overall acceptability. Fruit quality study results showed fruit coated with GA 15% + M and CMC 1% + M had lower mass loss (3.66%), retained firmness (62.37 N), and color changes [L* (30.85), a* (−2.33) and b* (7.14)] compared with other treatments. In this biofungicidal study on antimicrobial properties of extracts, treatments against fungi strains using an in vitro test were investigated, which showed treatments of moringa leaf extract, GA 10% + M, and GA 15% + M suppressed radial mycelial growth of C. gloeosporioides by 30%, 28%, and 33%, respectively. In conclusion, our study demonstrated that GA 15% + M and CMC 1% + M retained fruit firmness and lowered weight loss and suppressed mycelial growth of C. gloeosporioides on ‘Maluma’ avocado fruit. These edible coatings could therefore be an alternative organic postharvest coating treatment and could potentially be commercialized as a new organic biofungicide for the avocado fruit industry.