Even though Saudi EFL students devote multiple years to improving their English-speaking proficiency, they struggle to achieve fluency. The present study, however, focuses on investigating the effectiveness of using Duolingo in EFL classrooms to enhance the participants' speaking proficiency. The participants who underwent this study were 28 male Saudi students studying in secondary school, namely at Sharia Institute. They were divided into control and experimental groups. Data was collected via post-test to conduct a valid comparison between the two groups. The 14 students in the experimental group had been using Duolingo for a period of four consecutive months while the participants in the control group have never used Duolingo. To make a valid comparison of the mean score between the two groups, an independent samples t-test was used in this experiment. After analysing the results, it has been concluded that the integration of Duolingo in the learning process has a fundamental positive impact on enhancing participants' speaking proficiency as well as improving their overall language skills. Additionally, the participants' positive attitude towards Duolingo was an intrinsic factor that helped alleviate their anxiety when speaking.