The current status of basic research in hypersonic turbulent ows is reviewed. We consider free shear layers, boundary layers, internal flows and shock-wave boundary layer interactions, and discuss experiments as well as computations, including DNS, LES, RANS and RANS-LES hybrid approaches. Important research challenges in external and internal hypersonic flows are identified and some possible future directions are explored. Some recent experimental and computational contributions are summarized. Copyright © Alexander J. Smits, M. Pino Martin, Sharath Girimaji.