| A Cappella Showcase | Waterdown |
| A Child's Voice Foundation, Mississauga | Mississauga |
| Ability Online Support Network, Mono - Online Service | Mono |
| Access Midwives, Midwifery Services | Hamilton |
| AccessOAP | Toronto |
| Active Aldershot Society | Burlington |
| Active Chefs | Oakville |
| Acton Aqua Ducks Swim Club | Acton |
| Acton Badminton Club, Recreational Badminton | Acton |
| Acton Curling Club | Acton |
| Acton Foodshare, Food Bank | Acton |
| Acton Skating Club | Acton |
| Acton Soccer Club | Acton |
| Adoption Council of Ontario | Toronto |
| African Community Services of Peel, Violence Against Women Program | Brampton |
| Aiza's Teddybear Foundation | Oakville |
| Aldershot Tennis Club | Burlington |
| Alpha's Discovery Kids Preschool and Daycare, Licensed Child Care Centre | Oakville |
| Alton Kids Child Care Center, Licensed Child Care Centre | Burlington |
| Anglican Church of the Incarnation | Oakville |
| Angus Valley Montessori, Licensed Child Care Centre | Milton |
| Anonymous Friend, Youth Peer to Peer Mental Health Support | Oakville |
| Appleby College, March Break Camps | Oakville |
| Appleby College, Newcomers Tutoring Program | Oakville |
| Appleby College, Summer Camp Programs | Oakville |
| Appleby Tennis Club | Burlington |
| Apples and Angels Montessori School and Day Care, Georgetown - 83 Main St, Licensed Child Care Centre | Georgetown |
| Apples and Angels Montessori School and Day Care, Georgetown - 79 Main St, Licensed Child Care Centre | Georgetown |
| ArtHouse for Children and Youth | Oakville |
| Arubah Kids Clinic | Mississauga |
| Ashwood Glen School, Licensed Child Care Centre | Burlington |
| Asperger's Society of Ontario | Toronto Downtown North |
| Association for Bright Children of Ontario, Halton Chapter | Halton Region |
| Association of Ontario Midwives | Toronto Downtown Central |
| Ausum Charity for Autism | Streetsville |
| Autism Ontario, Halton Chapter - Mailing Address | Burlington |
| Autism Ontario | Toronto Downtown West |
