Two flagpoles flying British Legion flags have been pulled off and snapped at the St Helier town church. The lectern was also pushed over and damaged during the attack on Sunday afternoon.
It is thought about �1,500 of damage was caused.
The lectern will have to be sent to the UK to be repaired.
Parish rector, the Reverend John Seaford, said: "It is sad that people misbehave in churches.
"But I'm mightily relieved that the damage was in fact minimal and all repairable."