Multichannel successive approximation register (SAR) analog-to-digital converters (ADC), along with methods and systems for multichannel SAR analog-to-digital conversion, are disclosed herein. An exemplary multichannel SAR ADC can include a first SAR ADC for each of a plurality of input channels, and a second SAR ADC, a multiplexer, and a residue amplifier shared among the plurality of input channels. The multiplexer can select an analog residue signal from one of the first SAR ADCs for conversion by the second SAR ADC. The residue amplifier can amplify the selected analog residue signal. The second SAR ADC, multiplexer, and/or residue amplifier may be shared among all of the plurality of input channels. Where the multichannel SAR ADC includes N input channels, the second SAR ADC, multiplexer, and/or residue amplifier may be shared among b channels of the N input channels.