Prolonged length of stay (LOS) in the emergency department (ED) is a key factor in measuring ED crowding worldwide. This study aimed to identify factors associated with prolonged LOS in the ED to better understand these factors at our institution. This was a retrospective record review examining factors associated with prolonged emergency department length of stay (>6-hours). Data were collected from electronic medical records, including patient demographics, chief complaints, triage acuity level, medication administration, diagnostic testing, consultations and patient disposition. In 2019, we recorded a total of 36,068 patient visits at our ED. Of these, 6439 (17.9%) patients met our definition of prolonged ED LOS (more than 6-hours) and were included in our analysis. Using multivariate analysis, we found that consulting services carried the highest predictor for prolonged ED LOS, with an adjusted odds ratio (aOR) of 23.0 and 95% confidence interval (CI) of 20.4–25.8. Followed by medication administration (aOR 2.0, CI 1.8–2.3), laboratory investigations (aOR 1.7, CI 1.5–2.0), radiological studies (aOR 1.8, CI 1.6–2.0), and non-Saudi nationality (aOR 1.3, CI 1.2–1.4), all p < 0.01. ED LOS may be reduced by optimizing the process of laboratory/radiology testing and medication administration. More importantly however, implementing a timeframe monitoring system for consultations while emphasizing accelerated decision-making and disposition for patients can reduce ED LOS.