The MGWR Class D were 2-4-0 steam locomotives built in batches from 1873 to 1887 for the Midland Great Western Railway (MGWR) of Ireland to a Martin Atock design.

Numbering 39 at their peak they were the standard MGWR passenger locomotive of their era.

[citation needed] The first batches from Neilsons and Dübs were withdrawn 1893–1898 and replaced by the more powerful MGWR Class K 2-4-0, which cascaded the remaining Class D's to secondary duties.

The batch of six Beyer-Peacock locomotives were selected for a rebuild to a 4-4-0 bogie design in 1900/01, the first use of such a configuration on the MGWR.

The rebuilt locomotives were found wanting for their intended use on the Sligo line west of Mullingar but nevertheless paved the way for the MGWR Class A and Class C 4-4-0s whilst doing useful work in the County Mayo and Achill areas.The remaining Kitson and Broadstone built members of the class were withdrawn between 1911 and 1922, being cascaded out by more powerful 4-4-0 passenger locomotives being introduced.