The invention relates to an adjusting phase of a digital phase-locked loop. Aspects of this disclosure relate to a digital phase-locked loop (DPLL) arranged to adjust output phase using a phase adjustment signal. In certain embodiments, the phase adjustment signal can be received in a signal path from an output of a time-to-digital converter of the DPLL to an input to the digitally controlled oscillator of the DPLL. Some embodiments relate to adjusting the output phase of the DPLL to reduce a relative phase difference between the output phase of the DPLL and an output phase of another DPLL.