Background: Poor sleep quality and psychological stress are interrelated and disproportionately affect adults with multiple cardiovascular disease (CVD) risk factors. Maintaining an optimal home environment and engaging in healthy bedtime behaviors are important components of sleep hygiene practices that influence sleep health and mental well-being. However, research is scarce in exploring the associations between sleep hygiene, sleep quality, and psychological stress among adults with multiple CVD risk factors. Methods: A cross-sectional study was conducted with 300 adults diagnosed with hypertension and type 2 diabetes. Individuals were recruited from a large academic health center and were asked to complete an online survey. Sleep hygiene was assessed by nine individual factors focusing on negative household environment (safety, physical comfort, temperature, and light) and poor bedtime behaviors (watching TV, playing video games, using small screens, and eating) and by a composite score. Multiple regression and mediation analysis with bootstrapping were employed to examine the associations. Results: Of the sample, 78% reported poor sleep quality and 44% reported high psychological stress. Individual sleep hygiene factors as well as the composite score were significantly associated with poorer sleep quality and higher psychological stress. Sleep quality mediated the association between the composite score and psychological stress (Indirect effect: 0.16; 95% bootstrap confidence interval: 0.04-0.35). Conclusions: The study highlights strong links between sleep hygiene, sleep quality, and psychological stress. Although causality cannot be established, current evidence suggests that promoting home environment and bedtime behaviors may alleviate sleep and psychological burdens in adults with multiple CVD risk factors.