Acoular is a framework for acoustic beamforming that is written in the Python programming language. It is aimed at applications in acoustic testing. Multichannel data recorded by a microphone array can be processed and analyzed in order to generate mappings of sound source distributions. The maps (acoustic photographs) can then be used to locate sources of interest and to characterize them using their spectra.A few highlights of the framework:covers several beamforming algorithmsdifferent advanced deconvolution algorithmsboth time-domain and frequency-domain operation included3D mapping possibleapplication for stationary and for moving targetssupports both scripting and graphical user interfaceefficient: intelligent caching, parallel computing with Numbaeasily extendible and well documented