HTC One M9 is an Android smartphone manufactured and marketed by HTC. The third-generation One was officially unveiled in a press conference at Mobile World Congress on March 1, 2015. It is the successor to the prior year's One M8.

The design of the M9 is similar to its predecessor, except that it is slightly narrower and thicker. It features an octa-core Qualcomm Snapdragon 810 system-on-chip with 3 GB of RAM, a 5-inch 1080p display, and 32 GB of internal storage (nearly 9 GB is reserved for the operating system). The UltraPixel image sensor (which had larger pixels in its sensor, but sacrificed megapixel size for enhanced low-light capabilities) was moved to the front-facing camera, with the rear-facing camera now using a more traditional 20 megapixel sensor, supporting 4K video recording. The M8's depth sensor was also dropped. Its front-facing "BoomSound" stereo speakers now use Dolby Audio tuning.

The M9 runs Android 5.0 "Lollipop" with HTC's Sense 7 user interface and software suite.