Joseph Michael MacDonagh (18 May 1883 – 25 December 1922) was an Irish Sinn Féin politician.

His parents Joseph MacDonagh and Mary Parker were both national schoolteachers.

[2] In January 1919, Sinn Féin MPs refused to recognise the Parliament of the United Kingdom and instead assembled at the Mansion House in Dublin as a revolutionary parliament called Dáil Éireann, though MacDonagh did not attend as he was in prison.

He also served as an alderman of Rathmines and Rathgar Urban District Council and Dublin Corporation between 1920 and 1922.

He was re-elected for the same constituency at the 1922 general election as an anti-Treaty Sinn Féin TD, but he did not take his seat in the Dáil.