Grevillea rosieri is a shrub of the genus Grevillea native to an area in the Wheatbelt region of Western Australia. The shrub typically grows to a height of 0.5 metres (2 ft) and has non-glaucous branchlets. It has simple flat linear undissected leaves with a blade that is 15 to 35 millimetres (1 to 1 in) long and 0.5 to 1.5 mm (0.02 to 0.06 in) wide. It blooms from July to September and produces an axillary raceme irregular inflorescence with red or brown flowers and red styles. Later it forms simple hariy ellipsoidal fruit that is 6 to 10 mm (0.2 to 0.4 in) long.