Gboyega Famodun, the state APC Chairman said this at a news conference on Thursday at the party secretariat, in Osogbo.
Mr Famodun said that the decision followed assurances by the party lawyers who said that there were good grounds to challenge the results after they had studied them.
“We are going to the tribunal. Our lawyers had informed us that we have good reasons to challenge the results of the election at the tribunal,” he said.
He decried the suspected anti-party activities of an APC faction in the state “The Osun Progressive (TOP).”
The chairman said that the faction, which was under the control of the Minister of Interior and former governor Rauf Aregbesola, worked for the opposition, the Peoples Democratic Party (PDP), to deny the APC victory at the election.
Governor Gboyega Oyetola of APC placed second with 375,027 votes.