Lally (also O'Mullally) (died 1691) was an Irish landowner and politician from Tuam, County Galway.
He was a leading member of the Gaelic clan of the O'Mullallys (in Irish Ó Maolalaidh), which was based in the parish of Tuam, County Galway.
Their lands comprised the lands known as Tulach na Dála (Anglicised as Tullindaly, Tullenadaly, Tullaghnadaly, or Tolendal), four miles north of Tuam town.
Lally sat as representative of Tuam Borough in King James II's Patriot Parliament of 1689.
He went to France in 1690 with his cousin, the Honourable Colonel Arthur Dillon, in whose regiment, as Colonel-Commandant, he was killed at Montmélian in 1691.