High-power, high-efficiency millimetre-wave oscillators were implemented in IBM 45 nm silicon-on-insulator (SOI) complementary metal-oxide semiconductor (CMOS). A voltage-controlled oscillator (VCO) was designed using a class-E power amplifier in a positive feedback configuration and an injection-locked oscillator (ILO) was implemented using a cross-coupled design with fundamental frequency injection at the device drains. The VCO exhibits an output power of 8.2 dBm and a peak efficiency of 15.64%. The tuneable range of the VCO is 45.5–47.5 GHz. The measured phase noise is −106.51 dBc/Hz at a 1 MHz offset. This VCO achieves the highest reported efficiency and output power for silicon-based monolithic millimetre-wave oscillators to the best of the authors' knowledge. The ILO exhibits a locking range of approximately 3 GHz for a −10 dBm injected signal and an output power of 5.2 dBm for the minimum injected locking power at its centre frequency of 45 GHz, yielding a power-added efficiency of 6.1%.