ScanIR is an application for flexible acoustic multichannel impulse response measurement in Matlab intended for public distribution. The application interfaces with the PortAudio API using Psychtoolbox-3, a toolkit in Matlab allowing high-precision control of a multichannel audio interface. ScanIR contains single-channel, binaural, and multichannel input modes, and it also allows the use of multiple output test signals. It is hoped that this application will prove useful to researchers using Matlab for physical or psychological acoustic measurements.