A voltage regulator with adaptive Miller compensation includes a first amplifier and a second amplifier. An adaptive compensation circuit includes serially connected compensation capacitor and a compensation transistor coupled to the second amplifier. A bias circuit generates a proper bias control voltage to dynamically control the adaptive compensation circuit in a manner that the adaptive compensation transistor operates in a deep triode region with weakly-inverted channel or strongly-inverted channel. An output circuit generates an output voltage according to which the feedback voltage is generated. The resistance of the compensation transistor varies according to a load of the voltage regulator under control of the bias control voltage. The bias circuit generates a mirror current that copies at least a portion of a current flowing in the output circuit, and the bias control voltage is then generated according to the mirror current.