Campbell, 25, appeared on the programme this week after reaching the 400m final at the British Athletics World Championships Team Trials last weekend.
The governing body said it expects athletes in contention for selection "to be 100% focused on their training and preparations to compete".
Campbell finished seventh in the 400m event in Birmingham.
He also competed for the men's 4x400m relay team at the IAAF World Relays in the Bahamas earlier this year but is on the fringes of the British squad. He is unlikely to feature as part of the relay squad at next month's World Championships in London.
Love Island is an ITV show that takes single participants to a villa in Majorca and they try to pair off to win £50,000.
British Athletics says it was "unaware" sprinter Theo Campbell was joining reality TV show Love Island.