Background <p>Sustainable dietary patterns are considered essential for both public health and environmental protection. This study aimed to evaluate sustainable nutrition behaviors, adherence to the EAT-Lancet dietary recommendations, diet quality, and obesity indicators among university staff.</p> Methods <p>This cross-sectional study was conducted with 120 university staff members. Participants were recruited using a convenience sampling method. Sociodemographic data, anthropometric measurements, the Sustainable and Healthy Eating Behaviors Scale (SHEB), the EAT-Lancet Diet Score, and the International Diet Quality Index (DQI-I) were collected. Robust regression analysis was conducted to identify the predictors of the EAT-Lancet Diet Score.</p> Results <p>The mean SHEB score was 134.3 ± 25. The median EAT-Lancet Diet Score and DQI-I were 9.0 (5.0–13.0) and 53.0 (33.0–69.0), respectively. A moderate positive correlation was found between the EAT-Lancet Diet Score and DQI-I (<i>r</i> = 0.586; <i>p</i> &lt; 0.001). Higher SHEB scores were observed among participants with postgraduate education (<i>p</i> &lt; 0.05). Negative associations were identified between the EAT-Lancet Diet Score and all anthropometric indicators, and between SHEB and BMI, waist (WC), and neck circumference (NC) (<i>p</i> &lt; 0.05). Regression analysis showed that men had significantly lower EAT-Lancet Diet Scores than women (<i>β</i> = -1.084, 95% CI: -1.68 to -0.488, <i>p</i> = 0.001). Each one-unit increase in SHEB score was associated with a 0.016 unit increase in EAT-Lancet Diet Score (95% CI: 0.016 (0.005–0.028), <i>p</i> = 0.006).</p> Conclusions <p>Gender and sustainable nutrition behaviors appear to be associated with adherence to the EAT-Lancet dietary recommendations. These findings highlight the need to promote sustainable eating behaviors in educational settings to support public health and environmental goals.</p> <i>Trial registration</i> <p>NCT06100666.</p>