Background: The actions and responses of the hospital personnel during acute stroke care in the emergency department (ED) may differ according to the severity of a patient’s stroke symptoms. We investigated whether the time from arrival at ED to various care steps differed between patients with minor and non-minor stroke who were treated with intravenous tissue plasminogen activator (IV tPA). Methods: We included consecutive patients who received IV tPA during a 1.5 year-period in 5 hospitals. Minor stroke was defined as a National Institutes of Health Stroke Scale (NIHSS) score < 5. We compared various intervals from arrival at the ED to treatment between patients with minor stroke and those with non-minor stroke (NIHSS score ≥5). Delayed treatment was defined as a door-to-needle time > 40 min. Results: During the study period, 356 patients received IV tPA treatment. The median door-to-needle time was significantly longer in the minor stroke group than it was in the non-minor stroke group (43 min [interquartile range [IQR] 35.5–55.5] vs. 37 min [IQR 30–46], p < 0.001). The minor stroke group had a significantly longer door-to-notification time (7 min [IQR 4.5–12] vs. 5 min [IQR 3–8], p < 0.001) and door-to-imaging time (20 min [IQR 15–26.5] vs. 16 min [IQR 11–21], p < 0.001) than did the non-minor stroke group. However, the imaging-to-needle time was not different between the groups. Multivariable analyses revealed that minor stroke was associated with delayed treatment (OR 2.54 [95% CI 1.52–4.30], p = 0.001). Conclusions: Our findings show that the door-to-needle time was longer in patients with minor stroke than it was in those with non-minor stroke, mainly owing to delayed action in the initial steps of neurology notification and imaging. Our findings suggest that some quality improvement initiatives are necessary for patients with suspected stroke with minor symptoms.