The Montgomery Guards were an Irish-American militia company that formed in Boston in 1837 and were forced to disband the following year due to extreme nativist and anti-Catholic sentiment in the city.

On September 12, 1837, at the annual fall muster on Boston Common, six companies of militiamen marched off the field to protest the inclusion of the Montgomery Guards. Afterwards, as the company's forty members marched down Tremont Street to their armory, they were mobbed by about 3,000 angry spectators who pelted them with bottles and rocks and threatened to storm the building.

City officials and the press strongly denounced the riot and praised the Montgomery Guards for their restraint. Nevertheless, Governor Edward Everett ordered the disbandment of the company for public safety reasons. Another company by the same name was formed sometime after the American Civil War.

After the War of 1812, the size of the U.S. Army was greatly reduced, and a large number of volunteer militia companies sprang up across the country to fill the gap. The militias protected local people and property during times of war and civil unrest. They also served a social purpose. In addition to regular drills and inspections, volunteers attended banquets, dances, and parades, where their smart-looking uniforms attracted envy and attention. For working-class men it was a way to gain social status and attract women, and for immigrants in particular it was a chance to display their loyalty to their new country.

In January 1837, several Irish Americans from Boston petitioned Governor Edward Everett for permission to form their own company. In the past, similar requests by Irish residents had been declined, but this time the petition came with the recommendation of the highest-ranking officers in the militia, and the request was granted. The new group, composed of eight naturalized Irish immigrants and thirty-two native-born citizens of Irish descent, became the Tenth Company of Light Infantry, Regiment of Light Infantry, Third Brigade, First Division, Massachusetts Volunteer Militia—otherwise known as the Montgomery Guards.

The new company was one of several Irish-American militia companies named for Richard Montgomery, an Irish-born general who had served in the Continental Army; others were started in New York, Philadelphia, and New Orleans. Among the organizers of the Boston company was the philanthropist Andrew Carney, who was then a partner in a clothing firm that supplied the U.S. Navy with uniforms. Thus the Montgomery Guards of Boston were provided with custom-designed green uniforms with scarlet facings and gold trim, and caps bearing their own company emblem: an American eagle alighting on an Irish harp. Their motto, borrowed from the Charitable Irish Society, was "Fostered under thy wings, we will die in thy defense."

They were first called to duty on June 11, to help quell the Broad Street Riot. City officials and the local press commended their performance, and a week later the governor himself reviewed their first parade, which was followed by a formal banquet at the Concert Hall.

This auspicious beginning did not reflect the attitude of most Bostonians toward Irish Catholics. While Boston's elites welcomed the new company, others were horrified by the thought of Irishmen being provided with weapons and military training. Anti-Catholic literature of the time depicted Irish immigrants as part of a "papist" conspiracy to take over the country. Rumors circulated that the governor had succumbed to "foreign influence," and resentment simmered among the other companies at being forced to accept people they saw as dangerous outsiders into their regiment.