Hampus Wilhelm Arnell (2 August 1848 in Härnösand – 1932 in Uppsala) was a Swedish bryologist.
In 1875, he became a privat-docent of botany at the University of Uppsala, later working as a schoolteacher in Umeå and Harnosand.
In 1880 he became an associate professor of natural history and chemistry in Jönköping.
[1] His botanical studies included trips throughout most of Sweden, to northern Norway (1869, 1870 and 1891) and to the lower Yenisei valley in Siberia (1876).
[1] From 1873 onward, he performed phenological research in various parts of Sweden.