BACKGROUND:Lower care quality and an increase in adverse outcomes as a result of new medical trainees is a concept well rooted in popular belief, termed the "July phenomenon." Whether this phenomenon occurs in acute ischemic stroke has not been well studied. METHODS AND RESULTS:We analyzed data from patients admitted with ischemic stroke in 1625 hospitals participating in the Get With The Guidelines-Stroke program for the 5-year period between January 2009 and December 2013. We compared acute stroke treatment processes and in-hospitals outcomes among the 4 quarters (first quarter: July-September, last quarter: April-June) of the academic year. Multivariable logistic regression models were used to evaluate the relationship between academic year transition and processes measures. A total of 967 891 patients were included in the study. There was a statistically significant, but modest (<4 minutes or 5 percentage points) difference in distribution of or quality and clinical metrics including door-to-computerized tomography time, door-to-needle time, the proportion of patients with symptomatic intracranial hemorrhage within 36 hours of admission, and the proportion of patients who received defect-free care in stroke performance measures among academic year quarters (P<0.0001). In multivariable analyses, there was no evidence that quarter 1 of the academic year was associated with lower quality of care or worse in-hospital outcomes in teaching and nonteaching hospitals. CONCLUSIONS:We found no evidence of the "July phenomenon" in patients with acute ischemic stroke among hospitals participating in the Get With The Guidelines-Stroke program.