Her music embraces many influences, particularly jazz and Scottish traditional music, in a catalogue boasting over 200 compositions including solo, duo, chamber, orchestra, vocal, choral, theatre and opera works. Her music has been broadcast and performed extensively around the world with notable soloists including Steven Isserlis, James Crabb, Colin Currie and Tabea Zimmermann amongst others.

Celtic themes are often present in Beamish’s music. One such piece, <em>Reed Stanzas</em>, for the Elias Quartet, received its premiere at the 2011 BBC Proms and won a Royal Philharmonic Society Award. Flodden, written for the Scottish Chamber Orchestra to commemorate the 500th anniversary of the eponymous battle, was premiered in September 2013 and shortlisted for both a Royal Philharmonic Society and BASCA British Composer Award. A year later, Equal Voices, for the London Symphony Orchestra, Royal Scottish National Orchestra and their choruses, with text by Sir Andrew Motion, was premiered at the Barbican Centre to commemorate the centenary of the start of the First World War. Spinal Chords, one of the PRS 20x12 Olympic commissions, with text by The Times Journalist Melanie Reid, toured the UK in 2014 with the Orchestra of the Age of Enlightenment and narrator Juliet Stevenson.

Since 1999 Sally has been championed by the BIS record label, which has recorded much of her work. Most recently, 2015's The Singing was released to critical acclaim and features her accordion concerto of the same name with James Crabb, and further includes Under the Wing of the Rock with saxophonist Branford Marsalis and Beamish’s Trumpet Concerto with Håkan Hardenberger.

Sally is in high demand, in her 60th birthday year, with upcoming works for 2016 including two works as part of Shakespeare 400: a full-length ballet of The Tempest for Birmingham Royal Ballet and Houston Ballet, with choreographer David Bintley, and A Shakespeare Masque with Poet Laureate, Carol Ann Duffy, for Ex Cathedra. She will complete three piano concertos this year with the first, for Ronald Brautigam, receiving its world premiere with the Amsterdam Sinfonietta in March 2016. Further performances will take place throughout the year with Orchestra Filarmonica di Torino, Orchestre de Picardie and Norrlandsoperan Symphony Orchestra.