HarmonyOS (HMOS) (Chinese: 鸿蒙; pinyin: Hóngméng; trans. "Vast Mist") is a distributed operating system developed by Huawei for smartphones, tablets, smart TVs, smart watches, personal computers and other smart devices. It has a microkernel design with a single framework: the operating system selects suitable kernels from the abstraction layer in the case of devices that use diverse resources.
HarmonyOS was officially launched by Huawei, and first used in Honor smart TVs, in August 2019. It was later used in Huawei wireless routers, IoT in 2020, followed by smartphones, tablets and smartwatches from June 2021.
From 2019 to 2024, versions 1 to 4 of the operating system were based on code from the Android Open Source Project (AOSP) and the Linux kernel; many Android apps could be sideloaded on HarmonyOS.
The next iteration of HarmonyOS became known as HarmonyOS NEXT. HarmonyOS NEXT was announced on August 4, 2023, and officially launched on October 22, 2024. It replaced the OpenHarmony multi-kernel system with its own HarmonyOS microkernel at its core and removed all Android code. Since version 5, HarmonyOS only supports apps in its native "App" format.
In May 2025, the first notebook with the HarmonyOS operating system was launched by Huawei, featuring "HarmonyOS PC", i.e. HarmonyOS NEXT 5 for the personal computer form factor.