The Acoustical Association Ontario (AAO) is an association representing unionized employers engaged in Acoustic and Drywall construction in the Industrial, Commercial and Institutional sector of the construction industry in the Province of Ontario.

The association was established in 1963 to represent acoustical ceiling and drywall contractors in collective bargaining. Today AAO is involved in a range of activities including Industrial Relations, Occupational Health & Safety, Apprenticeship Training, and Government Relations.