Two people sustained serious burns in the early hours of Monday Morning.
Burning material was put through the letterboxes of two separate properties in Jericho at around 2.45am- one on Kingston Road and the other in Plantation Road.
Two people were taken to the John Radcliffe Hospital for treatment.
A 30 year-old man from Stratford-upon-Avon has been arrested on suspicion of arson with intent to endanger life. He is currently in custody in Warwickshire.
Meanwhile, police are continuing to investigate what happened and are appealing for information and footage.