Mobile accessibility ensures that applications built for iOS and Android devices are usable by people with diverse abilities, including those who rely on screen readers, switch controls, or alternative input methods. Both platforms provide robust accessibility frameworks—UIAccessibility on iOS and Android's AccessibilityNodeInfo system—that translate UI elements into information assistive technologies can interpret. Understanding how to properly configure accessibility labels, manage focus order, and test with VoiceOver and TalkBack transforms mobile apps from technically functional to genuinely inclusive. The key insight: accessibility is not a feature to bolt on at the end, but a fundamental design consideration that improves usability for everyone.