Background The association between systemic hypertension and cerebrovascular disease is well documented. However, the impact of pulmonary hypertension (PH) on acute ischemic stroke outcomes is unknown despite PH being recognized as a risk factor for acute ischemic stroke. We aimed to determine the association between PH and adverse in‐hospital outcomes after acute ischemic stroke, as well as whether there are sex differences in this association. Methods and Results Acute ischemic stroke admissions from the US National Inpatient Sample between October 2015 and December 2017 were included. The relationship between PH and outcomes (mortality, prolonged hospitalization >4 days, and routine home discharge) was analyzed using logistic regressions adjusting for demographics, comorbidities, and revascularization therapies. Interaction terms between PH and sex and age groups were also included. A total of 221 249 records representative of 1 106 045 admissions were included; 2.9% of patients had co‐morbid PH, and 35.34% of those were male. PH was not associated with in‐hospital mortality (odds ratio [OR], 0.96; 95% CI, 0.86–1.09) but was associated with increased odds of prolonged hospitalization (OR, 1.15; 95% CI, 1.09–1.22) and decreased odds of routine discharge (OR, 0.87; 95% CI, 0.81–0.94) for both sexes. Older patients with PH were significantly less likely to be discharged routinely ( P =0.028) than their younger counterparts. Compared with female patients with PH, men were 31% more likely to die in hospital ( P =0.024). Conclusions PH was not significantly associated with in‐hospital mortality but was associated with prolonged hospitalization and adverse discharge status. Male patients with PH were more likely to die in hospital than female patients.