Laser speckle imaging (LSI) as a label-free flow mapping technique has numerous potential clinical applications and plays an increasingly important role in translational medicine. Conventional LSI, however, is limited to qualitative flow change assessment and two-dimensional topographic imaging. Here we report a light-sheet laser speckle imaging (LSH-LSI) platform. This new technique takes advantage of the optical sectioning capability inherent in selected plane illumination to achieve tomographic imaging of vascular structures and blood flow velocity with high spatiotemporal resolution. We conducted on this novel platform zebrafish imaging experiments to reveal complicated laser speckle dynamic characteristics, for which revised theoretical models were necessary for quantitatively retrieving the flow velocity. Furthermore, LSH-LSI could generate vector velocity maps based on additional processing of scalar laser speckle velocimetry results acquired at high frame rates.