The WAGR Oas class were a pair of experimental steam locomotives operated by the Western Australian Government Railways (WAGR) from 1934 to 1946.

The Oas class were the result of fitting superheated boilers to two Oa class No. 2 and No. 160. With No. 2 refitted in 1934 and No. 160 in 1938. Both were reconverted to Oa class locos in 1946 with both engines renumbered in 1949 to No. 171 and No. 178 and both were also withdrawn and scrapped in 1961.