The Upper School choral program offers several ensembles to suit a variety of interests and skill levels:

• The Mahertians: A co-ed group of Brunswick and Greenwich Academy students.
• The Twelve: A select ensemble of 12 singers who rehearse twice weekly.
• The Men of Brunswick: A male a cappella group drawn from the Mahertians and the Twelve, performing complex harmonies ranging from bebop to rock.

Smaller quartets and octets are also encouraged to form, rehearse, and perform independently. These groups regularly perform at school events such as parent open houses, holiday and spring concerts, and graduation, as well as at various community venues throughout the year.