Walter Wade, MD (died 1825) was an Irish physician and botanist.
Wade was a physician practising at the Dublin General Dispensary in Dublin in 1790. Aylmer Bourke Lambert in a letter to (Sir) James Edward Smith states that through Wade's exertions a grant of £300 was obtained to establish the botanic garden at Dublin, and that he intended to publish a work entitled Flora Dublinensis. Undated folio sheets of this proposed work exist, with plates, under the title Floræ Dublinensis Specimen, but it was never carried out. Wade eventually became Director of the botanic garden until his death in 1825.
In 1794, Wade published Catalogus Systematicus Plantarum indigenarum in comitatu Dublinensi … pars prima, on the title-page of which he describes himself as a medical doctor, licentiate of the King's and Queen's College of Physicians, and lecturer on botany. This work is in Latin (275 pages 8vo), arranged on the Linnæan system, with carefully verified localities and indexes of the Latin, English, and Irish names. The sedges and cryptogamic plants were reserved for a second part, which was never published. Lady Kane, in her anonymous Irish Flora (Dublin, 1833), says of this work (preface, p. vii) that it was "the first that appeared in Ireland under a systematic arrangement", and that its author "may be justly considered as the first who diffused a general taste for botany in this country".
Wade visited various parts of Ireland in search of plants in 1796. He was Lecturer on Botany at the Royal College of Surgeons and was elected a Fellow of the Royal Society in 1811.