ROSO was formed in 1985 of both sexes under the aegis of Royal Guard.
In 1987 they performed under the auspices of H.M. Sultan Qaboos and in public for the first time.
In 1989, performed another concert after being a full independent orchestra.
In 1990, His Majesty directed that a new orchestra complex to be established in Maqamat. The new complex was built in an area of 25,000 squared mitres and contained of 140 wings, mosque, offices, class rooms, auditorium and their supplements.
In 1996 ROSO played with BBC Philharmonic Orchestra.
In 1997, the number of players reached around 85 musicians who most of them passed grade 8 from the Associated Board of the Royal Schools of Music(ABRSM) in London.
In March 1998, ROSO performed 2 concerts in United Arab Emirates for Dubai Shopping Festival, the first one was in World Congress Centre and the second one was in World Trade Centre. Both of these concerts were conducted by Christopher Adey.
In 1999, performed a full concert with some of the world's well known opera singers on the opening cermony of Al-Fleij Castle in Barka (Al-Fleij).
Around 124 male and female students are now studying in ROSO's camp.
In November 2000 international opera singers Anthony Stuart Lloyd (Bass-Baritone) and Catherine Foster (Soprano), had the privilege of joing the Royal Oman Symphony Orchestra and Musical Director John Forster for a Private Royal Command Performance at the Bait al-Barakah Palace Concert House in the presence of His Majesty The Sultan in honour of his 30th Jubilee and 60th Birthday Celebrations. Due to the success of this concert Anthony and Catherine were invited back in April '01 to join the ROSO for a public gala of 'Grand Opera' at the Oman Auditorium, Al Bustan Palace Hotel. The feedback from the audience was tremendous and the Management at the Al Bustan explained that they had never sensed such a 'buzz' of excitement from an audience before.