Apparatus and methods for frequency lock enhancement of phase-locked loops (PLLs) are provided. In one aspect, a PLL can include a VCO having a tuning voltage input and a frequency tuning circuit configured to set a frequency band setting of the VCO. The frequency tuning circuit can include a voltage monitor configured to compare the voltage level of the tuning voltage input to one or more tuning voltage threshold levels, a control circuit configured to control at least a frequency band setting and a bias current setting of the VCO, and an amplitude detection circuit configured to compare an amplitude of an oscillation signal of the VCO to one or more amplitude threshold levels.