Brillouin light scattering (BLS) spectroscopy is a non-invasive, non-contact, label-free optical technique that can provide information on the mechanical properties of a material on the submicrometre scale. Over the past decade, BLS has found increasing microscopy applications in the life sciences, driven by the observed importance of mechanical properties in biological processes, the realization of more sensitive BLS spectrometers and the extension of BLS to an imaging modality. As with other spectroscopic techniques, BLS measurements detect not only signals that are characteristic of the investigated sample, but also those of the experimental apparatus, and can be substantially affected by measurement conditions. Here we report a consensus between researchers in the field. We aim to improve the comparability of BLS studies by providing reporting recommendations for the measured parameters and detailing common artefacts. Given that most BLS studies of biological matter are still at proof-of-concept stages and use different, often self-built, spectrometers, a consensus statement is particularly timely to ensure unified advancement.