Gilla na Naemh Crom Ó Seachnasaigh (died 1224) was an Irish Chief of the Name.
Ó Seachnasaigh was lord of Cenél Áeda na hEchtge, but is only recorded in the Irish annals towards the end of his era.
Only three more Ó Seachnasaigh's would be named in the annals before the 16th century (1240, 1403, 1408), none of them chiefs.
Thus the succession of the lordship is unclear till c. 1533.