Apparatus and methods for multiphase oscillators are provided. In certain implementations, an oscillator system includes a first multiphase oscillator and a second multiphase oscillator that are phase and frequency-locked. Additionally, the first and second multiphase oscillators are phase-locked by an amount of phase shift that provides colocated clock signal phases of relatively wide angular distances, which can be used by the oscillators' amplification circuits. The first and/or second multiphase oscillators include one or more amplification circuits that operate using at least one clock signal phase generated by the first multiphase oscillator and using at least one clock signal phase generated by the second multiphase oscillator.