Silicon RF power amplifiers (PAs) are in various RF front end modules (FEMs) today for handset and WLAN applications. Even though III-V semiconductor-based RF PAs can still offer superior frequency and breakdown performance with higher POUT and power-added-efficiency (PAE) and faster time-to-market, silicon-based RF PAs do have the advantages in offering higher monolithic integration with added functionalities (e.g., on-chip digital control and selection on power level, modulation, frequency band, matching, predistortion, etc.), which can translate to lower cost and smaller sizes attractive for broadband multi-mode multi-band handset transmitters. Therefore, some key techniques for designing high-efficiency 4G/5G/WLAN broadband wireless silicon PAs will be discussed.