Weight loss maintenance is crucial for obesity management, yet optimal dietary patterns for this period are not established. We aimed to explore the relationship between adherence to the Mediterranean Diet and weight loss maintenance. Sample includes 565 adults (62% women) of the MedWeight study. Eligible volunteers were those reporting intentional weight loss of ≥10%, starting from a BMI≥25 kg/m2, over 12 months prior to enrollment. Based on current weight, participants were characterized as maintainers (≤90% max weight), or regainers (>95% max weight). Socio-demographics and weight history were recorded. Dietary intake was assessed by 2 non-consecutive 24-hour recalls within 10 days, and analyzed in energy, macronutrient, and food group intake. Adherence to the Mediterranean Diet was assessed with the MedDietScore (range 0-55, greater scores showing higher adherence). Protein intake was higher in maintainers than regainers (p<0.001). When MedDietScore quartiles were considered, a linear trend for weight loss maintenance was revealed (p<0.05). After adjustment for demographics, being in the 3rd or 4th quartile of the MedDietScore (vs. 1st) associated with 2.30 (95%CI 1.29-4.09) and 1.88 (95%CI 1.10-3.22) increased odds of maintenance. Regarding individual MedDietScore components, only fruit intake associated with increased odds for maintenance [1.03 (95%CI 1.01-1.06)]. Leave-one-out approach revealed that at least 6 MedDietScore components were essential for the observed relationship. Higher adherence to the Mediterranean Diet was associated with 2-fold increased likelihood of weight loss maintenance. Future studies should replicate these findings in non-Mediterranean populations as well.