In light sheet-based fluorescence microscopy (LSFM), only the focal plane is illuminated by a laser light sheet. Hence, only the fluorophores within a thin volume of the specimen are excited. This reduces photo-bleaching and photo-toxic effects by several orders of magnitude compared with any other form of microscopy. Therefore, LSFM (aka single/selective-plane illumination microscopy [SPIM] or digitally scanned light sheet microscopy [DSLM]) is the technique of choice for the three-dimensional imaging of live or fixed and of small or large three-dimensional specimens. The parallel recording of millions of pixels with modern cameras provides an extremely fast acquisition speed. Recent developments address the penetration depth, the resolution and the recording speed of LSFM. The impact of LSFM on research areas such as three-dimensional cell cultures, neurosciences, plant biology and developmental biology is increasing at a rapid pace. The development of high-throughput LSFM is the next leap forward, allowing the application of LSFM in toxicology and drug discovery screening.