Abstract Allergic rhinoconjuncitivitis can be highly symptomatic and burdensome and complicates the management of eyelid and facial dermatitis in persons with atopic dermatitis (AD). However, little is known about the prevalence, burden and predictors of allergic rhinoconjunctivitis symptoms in patients with AD, particularly among adults. This study aims to determine the prevalence and predictors of allergic rhinoconjunctivitis severity in patients with AD. A cross-sectional, dermatology practice-based study was performed at an urban academic medical center (n = 507). Atopic dermatitis severity was assessed by investigator-assessed Eczema Area and Severity Index (EASI), body surface area (BSA), investigator’s global assessment (IGA), objective-SCORing AD and patient-reported Global Assessment (PtGA). Impact of allergic rhinoconjunctivitis symptoms was assessed by Rhinoconjunctivitis Quality of Life Questionnaire. The cohort included children (<18 years; n = 36, 7.1%), young adults (18–49 years; n = 281, 55.4%) and older adults (≥50 years; n = 190, 37.5%), males (n = 219, 43.2%) and females (n = 288, 56.8%), Hispanics (n = 43, 8.5%), Blacks (n = 50, 9.9%), White non-Hispanics (n = 349, 68.8%), Asians (n = 51, 10.1%) and multiracial/other race (n = 14, 2.8%); 413 (81.5%) had private insurance. Overall, 246 (48.5%) reported a history of hay fever, and 15 (3.0%) and 416 (82.1%) of patients with AD reported having trouble with one or multiple rhinoconjunctivitis symptoms in the past 2 weeks; 30 (5.9%) and 365 (72.0%) of patients with AD had quite a bit or extreme trouble with one or multiple rhinoconjunctivitis symptoms, respectively. More severe AD overall (EASI, BSA, IGA and PtGA), as well as more severe facial dermatitis, flexural eczema and xerosis were associated with worse rhinoconjunctivitis symptoms, whereas, race, gender and presence of nummular dermatitis were generally not associated with rhinoconjunctivitis symptom severity. Quite a bit or extreme trouble from one or more rhinoconjunctivitis symptoms was reported in 39 (56.5%) patients with clear/almost clear, 85 (74.6%) mild, 135 (82.8%) moderate and 106 (84.8%) severe PtGA scores. In multivariable ordinal logistic regression models that controlled for demographics, AD severity was significantly associated with higher odds of a wide range of nasal and ocular symptoms, as well as rhinoconjunctivitis symptoms negatively impacting daily activities, causing sleep and practical problems, and negative emotions. Allergic rhinoconjunctivitis symptoms occurred in more than 4 out of 5 patients with AD overall, and almost 90% of patients with severe AD. Allergic rhinoconjunctivitis was more common in those with more severe AD, and particularly those with more severe facial dermatitis, flexural eczema and xerosis. Rhinconjunctivitis symptoms negatively impact the lives of patients with AD and warrant appropriate screening and management in clinical practice.