Abstract Background Leveraging a large nationwide study of Icelandic women, we aimed to narrow the evidence gap around female attention-deficit/hyperactivity disorder (ADHD) and cardiometabolic comorbidities by determining the prevalence of obesity, hypertension, type 2 diabetes, and cardiovascular diseases among women with ADHD and examine the association between cardiometabolic conditions and co-occurring ADHD with anxiety and mood disorders, alcoholism/substance use disorder (SUD), self-harm, and suicide attempts. Methods We conducted a cross-sectional analysis of the nationwide, all-female, population-based SAGA Cohort Study (n = 26,668). To ascertain diagnoses and symptoms, we used self-reported history of ADHD diagnoses, selected cardiometabolic conditions and psychiatric disorders, and measured current depressive, anxiety, and PTSD symptoms through appropriate questionnaires (PHQ-9, GAD-7, and PCL-5). We calculated age-adjusted prevalences of cardiometabolic conditions by women’s ADHD status and estimated adjusted prevalence ratios (PR) and 95% confidence intervals (CI), using modified Poisson regression models. Similarly, we assessed the association of cardiometabolic conditions and co-occurring ADHD with current psychiatric symptoms and psychiatric disorders, using adjusted PRs and 95% CIs. Results We identified 2299 (8.6%) women with a history of ADHD diagnosis. The age-adjusted prevalence of having at least one cardiometabolic condition was higher among women with ADHD (49.5%) than those without (41.7%), (PR = 1.19, 95% CI 1.14–1.25), with higher prevalence of all measured cardiometabolic conditions (myocardial infarctions (PR = 2.53, 95% CI 1.83-–3.49), type 2 diabetes (PR = 2.08, 95% CI 1.66–2.61), hypertension (PR = 1.23, 95% CI 1.12–1.34), and obesity (PR = 1.18, 95% CI 1.11–1.25)). Women with cardiometabolic conditions and co-occurring ADHD had, compared with those without ADHD, substantially increased prevalence of (a) all measured mood and anxiety disorders, e.g., depression (PR = 2.38, 95% CI 2.19–2.58), bipolar disorder (PR = 4.81, 95% CI 3.65–6.35), posttraumatic stress disorder (PR = 2.78, 95% CI 2.52–3.07), social phobia (PR = 2.96, 95% CI 2.64–3.32); (b) moderate/severe depressive, anxiety, and PTSD symptoms with PR = 1.76 (95% CI 1.67–1.85), PR = 1.97 (95% CI 1.82–2.12), and PR = 2.01 (95% CI 1.88–2.15), respectively; (c) alcoholism/SUD, PR = 4.79 (95% CI 3.90–5.89); and (d) self-harm, PR = 1.47 (95% CI 1.29–1.67) and suicide attempts, PR = 2.37 (95% CI 2.05–2.73). Conclusions ADHD is overrepresented among women with cardiometabolic conditions and contributes substantially to other psychiatric comorbidities among women with cardiometabolic conditions.