A sinfonietta is a musical group that is larger than a chamber ensemble but smaller than a full-size or symphony orchestra.
There are many orchestras called sinfonietta. Some groups are still a sinfonietta despite not including the word in their name:
Stuart Oliver Knussen was a British composer and conductor.
Thomas Joseph Edmund Adès is a British composer, pianist and conductor. Five compositions by Adès received votes in the 2017 Classic Voice poll of the greatest works of art music since 2000: The Tempest (2004), Violin Concerto (2005), Tevot (2007), In Seven Days (2008), and Polaris (2010).
The Boston Youth Symphony Orchestras (BYSO) is a youth orchestra based in Boston, Massachusetts under the artistic leadership of music director, Federico Cortese. Since 1958, BYSO has served thousands of young musicians from throughout New England with three full symphonic orchestras, two young string training orchestras, six chamber orchestras, a preparatory wind ensemble, a chamber music program and a nationally recognized instrument training program for underrepresented youth from inner-city communities called the Intensive Community Program (ICP). The 2017-2018 season marks the celebration of BYSO's 60th Anniversary. Each year, BYSO auditions approximately 850 students from throughout New England, ages 5–18, and accepts nearly 500 young musicians.
The American Youth Philharmonic Orchestras (AYPO) are a group of youth orchestras in the Washington metropolitan area. The group consists of three full orchestras, and three string orchestras, along with several chamber ensembles and community outreach organizations. Currently, over 430 young musicians take part in AYPO programs.
Philip Cashian is an English composer. He is the head of composition at the Royal Academy of Music.
Simon Holt is an English composer.
Harold Farberman was an American conductor, composer and percussionist.
Colin Michael Touchin was a British conductor, composer and music educator. His compositions include two oratorios, four orchestral sinfoniettas, and works for wind band and choral groups.
James Crabb is a Scottish classical accordion player.
Diego Masson is a French conductor, composer, and percussionist.
Based in Baltimore, Maryland, four ensembles comprise the GBYO, the full-sized symphonic Youth Orchestra, the intermediate-level Concert Orchestra, and the beginning-level Sinfonia and Sinfonietta ensembles. GBYO also offers a "Bridges" program, providing entry-level instruction to underserved youth in the city. The GBYO ensembles are in residence at Loyola College in Maryland.
Richard Causton is an English composer and teacher.
David Sawer, is a British composer of opera and choral, orchestral and chamber music.
Huw Thomas Watkins is a British composer and pianist. Born in South Wales, he studied piano and composition at Chetham's School of Music in Manchester, where he received piano lessons from Peter Lawson. He then went on to read music at King's College, Cambridge, where he studied composition with Robin Holloway and Alexander Goehr, and completed an MMus in composition at the Royal College of Music, where he studied with Julian Anderson. Huw Watkins was awarded the Constant and Kit Lambert Junior Fellowship at the Royal College of Music, where he used to teach composition. He is currently Honorary Research Fellow at the Royal College of Music.
Christoph Poppen is a German conductor, violinist and academic teacher.
Martin Suckling is a British composer. He is also a violinist and teacher.
The Columbia Gorge Orchestra Association (CGOA) is a nonprofit organization that sponsors several performing ensembles in the Columbia River Gorge area of Oregon and Washington. Founded in 1978 as the Mid-Columbia Sinfonietta, the CGOA was created in 2005 and now encompasses six ensembles: Sinfonietta, Voci Choir, Jazz Collective, String Quartet (classical), Stages (musicals), and Youth Choir. As of 2020, Mark Steighner is the artistic director of the association.