Background <p>Over 339 million people worldwide suffer from asthma, a common and chronic illness affecting the airways. Treatment adherence is generally poor, with rates of less than 50% for children and 30–70% for adults. As smartphone usage continues to rise globally, mobile health (mHealth) technologies hold promise for enhancing self-care among asthma patients by offering support services such as information, educational resources, and behavior modification reminders.</p> Objective <p>To evaluate the role of a mobile application in reminding the patient to take his medication and the effects of this on quality of life, asthma control, and treatment adherence.</p> Methods <p>This is a randomized controlled clinical trial that included 264 asthmatic patients presenting to the outpatient clinic. Patients were randomized to a control group with usual asthma care and an intervention group that used an asthma reminder. Asthma Control Test, Morisky Medication Adherence Scale, and quality-of-life questionnaire were assessed in the previous and the following 3 months of usage.</p> Results <p>This study included 264 asthmatics (132 patients in the intervention group, 132 patients in the control group). During the follow-up visit after 3 months of randomization, there was a statistically significant higher mean of asthma-control tests (<i>P</i>-value &lt; 0.001), adherence score (<i>P</i>-value &lt; 0.001), and quality-of-life questionnaire (<i>P</i>-value &lt; 0.001) among the intervention group compared to the control group. Also, there were significantly lower exacerbations and hospitalizations (<i>P</i>-value = 0.036) in the intervention group.</p> Conclusion <p>Our study indicates that smartphone apps are an effective way to improve asthma control and treatment adherence. Poor adherent patients with chronic diseases must be encouraged to download a smartphone application that supplies information and reminds them about treatment on time.</p> Trial registration <p>ClinicalTrials.gov ID: NCT06233123.</p>