PowerPC G3 is a designation used by Apple Computer to a third generation of PowerPC microprocessors. The term is often, incorrectly, imagined to be a physical model of processor when in fact a number of processors from two different vendors have been used.

Such designations were applied to Apple Macintosh computers such as the PowerBook G3, the multicolored iMacs, iBooks and several desktops, including both the beige and blue and white Power Macintosh G3s. The low power requirements and small size made the processors ideal for laptops and the name lived out it's last days at Apple in the iBook.

Initial models of processor used were manufactured by Motorola namely the PPC 740 and PPC 750 - both derived from the earlier 603 with the PPC 750 offering an off-die level 2 backside cache. Both models were limited to 400 MHz and used an aluminium fabrication process. Later versions were manufactured by IBM utilising a "silicon on insulator" fabrication process achieving speeds of 800 MHz and beyond.

All models in this generation had issues with the symmetric multiprocessing capability which made design and manufacture of a multi-processor computer comparatively difficult which was not corrected until the PowerPC G4.