The time spent on the queue to get consulted by a doctor affects the patient’s satisfaction on the services provided by a hospital. Just like in the OPD of a public hospital in the Philippines, the researchers have observed poor queueing system where some patients are dissatisfied. To provide solutions to the existing problem, the researchers utilized SERVQUAL scale, five quality dimensions: tangibles, reliability, responsiveness, assurance, and empathy to assess service quality. Queueing theory and Promodel process simulation were also used to analyze the current queueing system and propose new layout. The result obtained shows a negative gap exists between the expectation and the observation of the patients with the service of the OPD in each dimension, which are tangibles (-0.4733), reliability (-0.2311), responsiveness (-0.1675), assurance (-0.3289), and empathy (-0.2258). In implementing the proposed layout, the results obtained were an 86% increase in the number of patients accommodated, a decrease of 40%, 6%, and 46% in the average time of patients in the system, in operation, and in the waiting time of patients, respectively, compared to the existing process. It has been demonstrated that the recommended layout model can improve the hospital's service quality while cutting down patient waiting time.