The British had taken the ground but at a great loss; they suffered 1,054 casualties (226 dead and 828 wounded), with a disproportionate number of these officers. The casualty count was the highest suffered by the British in any single encounter during the entire war. General Clinton, echoing Pyrrhus, remarked in his diary that "A few more such victories would have shortly put an end to British dominion in America." The Colonial losses were about 450, of whom 140, including Joseph Warren, were killed. Thirty men were captured, of whom 20 died while they were held prisoner. Most of the colonial losses came during the withdrawal. Major Andrew McClary was the highest ranking Colonial officer to die in the battle. He was later commemorated by the dedication of Fort McClary in Kittery, Maine.
British dead and wounded included 100 commissioned officers, a significant portion of the British officer corps in North America. Much of General Howe's field staff was among the casualties. Major Pitcairn had been killed, and Colonel James Abercrombie fatally wounded. General Gage, in his report after the battle, reported the following officer casualties (listing lieutenants and above by name):
* 1 lieutenant colonel killed
* 2 majors killed, 3 wounded
* 7 captains killed, 27 wounded
* 9 lieutenants killed, 32 wounded
* 15 sergeants killed, 42 wounded
* 1 drummer killed, 12 wounded