Objectives Asthma is a major public health problem affecting a large number of individuals worldwide. The effectiveness of medications depends on adherence to the instructions of the prescriber. This study aimed to assess and compare the effectiveness of a reminder card system versus a mobile application to improve the medication adherence of asthma patients in a tertiary care hospital. Methods This prospective interventional study was conducted at a tertiary care hospital. The scores were obtained from the Morisky medication adherence scale. Results In the card group, comparison of the baseline and follow-up scores for medication adherence showed a mean difference of 3.44, p = 0.001. The application group showed a mean difference of 4.02, p = 0.001, which reflects a highly significant association. Comparison of the effectiveness of reminder cards and the mobile application showed a mean difference of 0.72, p = 0.088 (>0.05) at baseline, showing no significant difference in adherence status before intervention. After intervention there was a mean difference of 0.86 ( p = 0.001 < 0.05), indicating a significant difference in adherence status. Conclusion Provision of proper interventional tools can improve asthma medication adherence. In this study, the mobile application was found to be more effective than medication reminder cards.