Wheeler's Surprise, and the ensuing siege of Brookfield, was a battle between Nipmuc Indians under Muttawmp, and the English colonists of the Massachusetts Bay Colony under the command of Thomas Wheeler and Captain Edward Hutchinson, in August 1675 during King Philip's War. The battle consisted of an initial ambush by the Nipmucs on Wheeler's unsuspecting party, followed by an attack on Brookfield, Massachusetts, and the consequent besieging of the remains of the colonial force. While the place where the siege part of the battle took place has always been known (at Ayers' Garrison in West Brookfield), the location of the initial ambush was a subject of extensive controversy among historians in the late nineteenth century.

After the death of the pro-English Massasoit in 1661, his son Metacom, known to the English colonists as "King Philip" initiated contacts with sachems of various tribes of New England to unite against the interests of the Plymouth Colony. The actual outbreak of war occurred on June 20, 1675, when a band of Pokanoket (a tribe of the Wampanoags) launched an attack on Swansea, Massachusetts, most likely without Metacom's approval, in retaliation for an earlier killing of a Pokanoket by an English colonists. In response, the colonists attacked and burned a Pokanoket village at Mount Hope.

Simultaneously the colonists sent Ephraim Curtis to the west of Boston into Nipmuc territory to negotiate with the tribe and obtain assurances of loyalty from them. However, Curtis' expedition party found only empty Nipmuc villages which signified that something was already afoot. Eventually, Curtis managed to find the whereabouts of the Nipmuc chief sachem, Muttawmp, and agreed to a meeting at a pre-arranged spot. However, unbeknownst to Curtis it was too late for negotiations, as the Nipmucs, under sachem Matoonas, had already attacked an English colonial settlement at Mendon and had decided to join Metacom's rebellion. Curtis was later joined by Captain Thomas Wheeler and Captain Edward Hutchinson (son of Anne Hutchinson).

Curtis and his men met with the Nipmuc sachem Muttawmp on July 14, the same day that another party of Nipmuc warriors was attacking Mendon. Hence, at the meeting, Muttawmp already considered himself to be at war with the English colonists. However, while Muttawmp's soldiers were rude to the English emissaries, the sachem himself considered it better to feign friendship to the colonists and so told Curtis that he would show himself in Boston within seven days.

After Curtis returned to Boston and informed his superiors of the arrangement, a decision was made not to wait for Muttawmp's arrival, but instead to send Captain Hutchinson, along with Captain Wheeler and 30 mounted militia, as well as some "Natick" Praying Indian guides to negotiate with the Nipmuc sachem directly. The party made their way to New Norwich where, on July 31, they found the village empty. Consequently, they learned that the Nipmucs had moved their base camp to about 10 miles (16 km) from Brookfield, and sent Curtis and the Naticks to talk to Muttawmp again. There, the emissaries were once again treated rudely by the Nipmuc braves, while Muttawmp continued his deception and agreed to meet Hutchinson in Brookfield on the following day.

However, when the colonists arrived in full force at the agreed spot the next day they found nothing. At that point the Natick guides tried to persuade the colonists to give up and return to Brookfield. Hutchinson and Wheeler, however, decided to march on to the Nipmuc camp, where they had met them the previous day.

In order to reach Muttawmp's camp, the colonists had to cross a swamp, taking a narrow path in single file. Despite more protestations from the Indian guides, Hutchinson and Wheeler decided to risk it, while at the same time aware that they might be walking into a trap.

In fact, after they proceeded for about 400 yards (370 m), Muttawmp's braves emerged from among the tall swamp grass and attacked them with bows and rifles. When the colonists turned around and tried to flee along the narrow path, they encountered another group of Nipmucs blocking their retreat. The colonial force was so completely disorganized that initially they were not even capable of returning fire. Both Hutchinson and Wheeler were seriously wounded. Eight other men were killed in the initial attack and several others were wounded.