The navigation of stem cells and progenitors to sites of tissue growth, the long-range extension of neuronal projections, and the large-scale movement of cells up or down external gradients all require shared molecular mechanisms that reshape the cytoskeleton in purposeful ways. Neutrophils, macrophages and other immune cells make use of these machineries to track and capture foreign entities. Disease may also depend on the motility of pathological cells, such as in cancer metastasis. In this Collection we aim to showcase primary research that significantly advances our understanding of the cell biological mechanisms regulating how cells move, from environmental cue sensing systems, to intracellular signaling pathways, to cytoskeletal machinery.