The extensive facilities of the Plaza Theatre have been utilised by groups staging Musicals, Operetta, Drama, Comedy, Meetings, Dance, Rock and Classical Music. The following list identifies a selection of the organisations that have staged events at the Plaza.

• Age Concern
• "Airs & Graces" - Linda Tedder
• All England Theatre Festival
• B&Q
• BBC
• Bournemouth Symphony Brass
• Eastleigh Operatic & Musical Society (Junior Section)
• Embley House Productions Theatre Company
• Fitzell-Roberts School of Dance
• Flautissimo
• Folklights
• Hampshire County Council
• Jane Mackinnon School of Dancing
• Junior Eastleigh Musical Society
• Kili Players
• Lanternfish Theatre Company
• Lewis Allsopp School Of Dance
• Marchwood Orchestra
• Mary Graham School of Dance
• Maskers Theatre Company
• Michelmersh Silver Band
• Monique French Cabaret
• Nicola McMillan School Of Dance
• Phoenix Theatre Company
• Players Theatre
• Richard Digance
• Romsey & District Buildings Preservation Trust
• Romsey Decorative and Fine Art Society
• Romsey School Big Band
• Rosemary Squires
• Sally Stannard School Of Dance
• Southampton Concert Wind Band
• Southern Minstrels
• Southern Theatre Productions
• Test Valley Borough Council
• World Machine