Microfluidics　that　permits　to　manipulate　fluids　at　the　micrometer　or　submicrometer　scale　offers　fundamentally　new　opportunities　in　chemical　and　biomedical　engineering.　The　past　decade　has　witnessed　considerable　progress　in　the　development　of　microfluidic　systems　for　use　in　micro-/nanomaterials　synthesis,　biosensing,　separation,　catalysis,　tissue　engineering,　and　so　on.　Among　many　microfluidic　mixers　to　enable　those　functions,　the　fusion　of　acoustics　and　microfluidics　(termed　acoustofluidics)　represents　an　emerging　promising　platform.　Acoustofluidics　can　manipulate　fluids　spatiotemporally　by　using　the　interaction　of　sound　waves　with　solids,　liquids,　and/or　gasses　in　a　confined　space　for　active　and　intensive　mixing.　This　review　accesses　the　utility　of　acoustofluidic　technology　in　chemical　and　biomedical　engineering　for　both　academic　research　and　industrial　applications.　We　summarize　the　established　categories　of　acoustic　micromixers　(sharp-edge,　bubble,　surface　acoustic　wave,　resonant　acoustic　mixing,　etc.),　discuss　the　underlying　principles,　highlight　the　current　achievements　for　diverse　lab-on-a-chip　application　fields　(chemical　synthesis,　biosensing,　protein　engineering,　separation,　cell　lysis,　etc.),　and　finally　set　out　the　practical　challenges　facing　acoustofluidics　to　inspire　future　research　in　this　field.　©　2021　Elsevier　Ltd