The concertmaster (from German Konzertmeister) is the spalla or leader of the first violin section of an orchestra. In the UK, the term commonly used is leader. Any violin solo in an orchestral work is played by the concertmaster (except in the case of a concerto, in which case a guest soloist usually plays). It is usually required that the concertmaster be the most skilled musician in the section, experienced at learning music quickly, and counting and observing the conductor for the rest of the section to follow. The concertmaster is the leader of not only the string section, but of the entire orchestra, subordinate only to the conductor.

The concertmaster sits to the director's left, closest to the audience, and makes decisions regarding bowing and other technical details of violin playing for the violins, and sometimes all of the string players. The concertmaster leads the orchestra in tuning before concerts and rehearsals, and other technical aspects of orchestra management.

The concertmaster in a standard wind band is the first-chair clarinet or oboe, and leads the ensemble's tuning. The first-chair clarinet concertmaster will, in common practice, play all solos for their instrument. Often the lead flautist will receive similar responsibilities to the clarinet concertmaster, depending on several factors such as age, skill and time spent in the ensemble. The concertmaster will, in both orchestral and wind band settings, also coordinate with other principals and section leaders, in most cases being their senior in terms of group pecking order. In brass bands this role is often filled by the principal solo cornet or trumpet.

The concertmaster has the duty of tuning the orchestra or band at rehearsals and performances, and also comes on stage individually. The concertmaster walks onstage prior to performing, takes a bow, shakes hands with the conductor, and receives applause on behalf of the ensemble. However, this practice is uncommon in Europe. There, the concertmaster walks onstage first, but is immediately followed by the rest of the orchestra. Thus the entire ensemble receives applause at the beginning and the concertmaster's role is less individual.