Quality assurance plays a vital role in mobile app development by ensuring that applications meet user expectations and function as intended. It involves testing for usability, performance, security, and compatibility across various devices and operating systems. Through rigorous testing processes, QA helps identify and rectify issues before launch, enhancing user experience and minimizing negative feedback after release. A solid quality assurance strategy can significantly reduce operational costs associated with post-launch fixes and improve app reliability. Ultimately, prioritizing quality assurance results in higher user satisfaction and better app retention.