Background/Objectives: Atopic dermatitis (AD) is a chronic inflammatory skin condition associated with psychological distress and diminished quality of life (QoL). The complex interplay between anxiety, depression, and multidimensional QoL in adults with AD remains insufficiently understood. This study aimed to examine the relationships and key predictors linking psychological distress and QoL in this population. Methods: In this cross-sectional study, 47 AD participants completed the Hospital Anxiety and Depression Scale (HADS) and World Health Organization Quality of Life (WHOQOL-BREF). Bivariate and multivariate analyses identified associations and predictors among anxiety, depression, and QoL domains. Results: Elevated anxiety (7.91 ± 3.27) and depression (6.28 ± 3.62) scores were observed, with moderate-to-poor QoL across all domains. Anxiety and depression were negatively correlated with all QoL dimensions (p < 0.05). Depression and stress predicted poorer self-perceived QoL (p < 0.001), and inadequate sleep was associated with lower environmental QoL (p = 0.006). Higher AD episode frequency correlated with reduced psychological QoL (p = 0.007). Conclusions: This study highlighted the substantial psychological burden and impaired QoL experienced by adults with AD, with depression, stress, and sleep quality serving as key modifiable factors. Integrated care addressing both physical and psychological factors is recommended to improve outcomes in this population. Future research should prioritize longitudinal designs and AD-specific assessments to further elucidate causal pathways and inform targeted interventions.