Conall mac Suibni (died 635), called Conall Guthbinn, was a King of Uisnech in Mide of the Clann Cholmáin. He was the son Suibne mac Colmáin (died 600), a previous king. He ruled from 621 to 635. His byname Guthbinn meant "sweet voiced".
His father Suibne had been killed in 600 by his uncle Áed Sláine mac Diarmato (died 604) eponymous ancestor of the Síl nÁedo Sláine. This set off a feud between the Clann Cholmáin and Síl nÁedo Sláine and in 604 a battle was fought in Faithche Mic Mencnain on the brink of Loch Semdid (Ballymore Loughsewdy in modern County Westmeath). In this battle Conall was able to witness the slaying of Áed Sláine slain by his foster brother Áed Gustan. Áed Sláine's allies; Áed Rón of the Uí Failge and Áed Buide, king of Tebtha; were also slain.
Of this feud, the Annals of Ulster record:
It was no time when counsel prevailed, for the warriors beyond Tuirbe: Conall slew Áed of Sláine, Áed Sláine slew Suibne.
Conall then succeeded to the kingship of Uisnech in 621 on the death of Óengus mac Colmáin, son of Colmán Bec. In 622 he defeated a rival cousinly line led by two sons of Librén, son of Illand, son of Cerball. Illand was a brother of his great-grandfather the high king Diarmait mac Cerbaill (died 565). This was fought at the Battle of Cenn Deilgthen (modern Kildalkey in County Meath) and Conall had the assistance of Domnall Brecc (died 642), later king of Dál Riata.
Conall next appears at the Battle of Áth Goan in western Liffey in 633. In this battle, he allied to Faílbe Flann mac Áedo Duib (died 637), the king of Munster, to assist Fáelán mac Colmáin (died 666?) of the Uí Dúnlainge in defeating and slaying Crimthann mac Áedo of the Uí Máil to acquire the throne of Leinster. The rise of the Ui Dunlainge to power appears to have been assisted by the Clann Cholmain who were looking to neutralize the border situation with the Ui Failgi so as to carry out their rivalry with the Síl nÁedo Sláine. Fáelán mac Colmáin was married to Conall's sister Uasal ingen Suibni (died 643).
Conall was now free to carry out the feud with Síl nÁedo Sláine. In 634, at the Battle of Loch Trethin at Fremainn (Loch Drethin at Frewin Hill, County Westmeath), he slew Congal mac Áedo Sláine, king of Brega, and his brother Ailill Cruitire. However, in 635 he was killed in the house of a certain Nad Fraích's son by Diarmait mac Áedo Sláine (died 665).
His son Airmetach Cáech was slain at the Battle of Mag Rath in 637 fighting for Congal Cáech of Ulaid versus the high king Domnall mac Áedo (died 642) of the Cenél Conaill. Airmetach's son Fáelchú was also slain in this battle. Airmetach's other son, Diarmait Dian mac Airmetaig Cáech (died 689), was a King of Uisnech.