| T. B. Radio Communications | Burlington |
| Tai Chi Healthy Bodies Healthy Minds | Milton |
| Take Off Pounds Sensibly, Georgetown Chapter, Weight Related Support Group | Georgetown |
| Take Off Pounds Sensibly, Burlington Chapter, Weight Related Support Group | Burlington |
| Take Off Pounds Sensibly, Milton Chapter, Weight Related Support Group | Milton |
| Talk4Healing, Telephone Helpline and On-line Chat Counselling Services | Thunder Bay |
| Talking for Change | Ontario |
| Tanglewood School, Licensed Child Care Centre | Oakville |
| Tarbiyah Elementary School, Milton | Milton |
| Taxi Services - Companies Serving Halton | Halton Region |
| Tech Coaches, Computer Literacy Training Programs | Halton Region |
| Technical Standards and Safety Authority | Toronto |
| Telling Tales, Literacy Promotion Programs and Events | Hamilton |
| TELUS Health MyCare | Toronto Downtown Central |
| Tempus Choral Society | Oakville |
| Ten Oaks Project, Ottawa | Ottawa |
| Tender Soles Footcare, Mobile Nursing Footcare | Burlington |
| Teresa Group - Child and Family Aid, Infant Formula Program | Toronto |
| Tetra Society of North America, Tetra Society Hamilton/Halton Chapter | Hamilton |
| The Angel Project Canada | Burlington |
| The Duke of Edinburgh's International Award - Ontario | Toronto |
| The Friends of the Old Seed House Garden, Showcase Garden | Georgetown |
| The Halton Resource Connection | Milton |
| The Halton Resource Connection, Child Care Directory and Information Line | Milton |
| The Halton Resource Connection, Professional Learning Services | Milton |
| The Halton Resource Connection, Resource Library | Milton |
| The Minor Surgery Centre, Oakville | Oakville |
| The Montessori Country School Milton, Licensed Child Care Centre | Milton |
| The Tomato Ladies | Oakville |
| Theatre Burlington | Burlington |
| Their Opportunity | Ottawa |
| TheKey, In-Home Care Services | Oakville |
| Therapeutic Paws of Canada, Milton Chapter | Milton |
| Thistlecreek Health Care - Home Care Services for Seniors, Oakville, In-Home Care Services | Oakville |
| Thistleoaks Child Care Centre, Licensed Child Care Centre | Oakville |
| Thompson Square Medical Centre | Milton |
| Thompson Square Pharmacy | Milton |
| Thompson Walk-In and Medical Clinic | Milton |
| Thornbrook Home Care | Etobicoke Central |
| Threads of Life - Association for Workplace Tragedy Family Support | London |
| Threshold School of Building, Threshold School of Building Ready to Work Youth Program | Hamilton |
| Thrive Counselling, Burlington Head Office | Burlington |
| Thrive Counselling, Caring Dads | Burlington |
| Thrive Counselling, Walk-in Counselling | Burlington |
| Thrive Counselling, Counselling Services | Burlington |
| Thrive Counselling, Milton Office | Milton |
| Thrive Counselling, North Halton Office | Georgetown |
| Thrive Counselling, Oakville Office | Oakville |
| Thrive Counselling, Partner Abuse Response Program | Burlington |
| Thrive Counselling, Supervised Parenting Time Program | Burlington |
| Thrive Counselling, The Safety Zone | Halton Region |
| Thrive Counselling, Violence Against Women Program | Halton Region |
| Thyroid Foundation of Canada | Bath |
| Time Changes, Exact Time and Time Zones | Canada |
| Tiny Hoppers Early Learning Centre, Burlington, Licensed Child Care Centre | Burlington |
| Tiny Hoppers Early Learning Centre, Milton - Sherwood Park, Licensed Child Care Centre | Milton |
| Toastmasters International, Find a Toastmasters Club | Ontario |
| Today's Family Early Learning and Child Care, Hamilton - Central Administration Office, Licensed Home Child Care Agency | Hamilton (City of) |
| Today's Family Early Learning and Child Care, Burlington - Alton Village Public School, Licensed Child Care Centre | Burlington |
| Today's Family Early Learning and Child Care, Burlington - Brant Hills Public School, Licensed Child Care Centre | Burlington |
| Today's Family Early Learning and Child Care, Burlington - C H Norton Public School, Licensed Child Care Centre | Burlington |
| Today's Family Early Learning and Child Care, Burlington - John William Boich Public School, Licensed Child Care Centre | Burlington |
| Today's Family Early Learning and Child Care, Oakville - Brookdale Public School, Licensed Child Care Centre | Oakville |
| Top Hat Marching Orchestra | Burlington |
| Toronto Abortion Clinic (The) | Toronto Downtown North |
| Toronto Military Family Resource Centre | Toronto |
| Toronto Pflag | Toronto |
| Toronto Public Library, Toronto - 789 Yonge St, Toronto Reference Library | Toronto |
| Toronto Wildlife Centre | Toronto |
| Total Care Transport Services | Milton |
| Total Contact Cast for Diabetic Foot Ulcers (The) | Halton Region |
| Total Health Pharmacy, Burlington - Harvester Rd, Pharmacy Services | Burlington |
| Total Health Pharmacy, Milton - Laurier Ave, Pharmacy Services | Milton |
| Total Health Pharmacy, Oakville - Oak Park Blvd, Pharmacy Services | Oakville |
| Total Health Pharmacy, Oakville - Nottinghill Gate, Pharmacy Services | Oakville |
| Total Health Pharmacy, Oakville - Morden Rd, Pharmacy Services | Oakville |
| Tottering Biped Theatre | Burlington |
| Tourette Canada | Brampton |
| Townsend Smith Foundation | Halton North |
| Trafalgar Oaks Child Care & Learning Centre, Licensed Child Care Centre | Oakville |
| Trafalgar Pharmacy, Pharmacy Services | Oakville |
| Trafalgar Presbyterian Church | Oakville |
| Trafalgar Ridge Montessori School, Licensed Child Care Centre | Oakville |
| Trafalgar Senior Homes, Rotary Centennial Towers | Oakville |
| Trafalgar Senior Homes, Woodside Mews | Oakville |
| Trafalgar Township Historical Society | Oakville |
| Trafalgar-Chartwell Residents' Association | Oakville |
| Trans Canada Trail, National Office | Montréal |
| Trans Lifeline | |
| Transforming Faith Worship Centre | Milton |
| TransUnion of Canada, Burlington, Consumer Relations | Burlington |
| Travel Industry Council of Ontario | Mississauga |
| Tribunals Ontario | Toronto |
| Trillium Health Partners, Credit Valley Hospital, Genetics Program | Mississauga |
| Trillium Health Partners, Credit Valley Emergency Department, Mississauga - Credit Valley Hospital | Mississauga |
| Trillium Health Partners, Credit Valley Hospital, Chronic Kidney Disease Program | Mississauga |
| Trillium Health Partners, Credit Valley Hospital, THP@home | Mississauga |
| Trillium Health Partners, Credit Valley Hospital | Mississauga |
| Trillium Health Partners, Mississauga Hospital, THP@home | Cooksville |
| Trillium Health Partners, Queensway Health Centre, Centre for Seniors' Medical Psychiatry - Outpatient Program | Etobicoke Central |
| Trillium Health Partners, Queensway Health Centre, Outpatient Physiotherapy Services (Progression) | Etobicoke Central |
| Trillium Health Partners, Queensway Health Centre, Seniors' Health Services - Regional Continence Home Visits Program | Etobicoke Central |
| Trillium Photographic Club | Burlington |
| Trinity Baptist Church | Burlington |
| Trinity Christian School | Burlington |
| Trinity United Church, Acton | Acton |
| Trinity United Church, Oakville | Oakville |
| Trio Medical Centre | Milton |
| True North Imaging, Oakville, Diagnostic imaging services | Oakville |
| TrueCare Medical Centre | Milton |
| TrueCare Medical Pharmacy, Pharmacy Services | Milton |
| Tuberous Sclerosis Canada Sclérose Tubéreuse | Barrie |
| Tuesday Night Mens Basketball | Oakville |
| Turning Point Youth Services, Toronto, TPYS Shelter | Toronto |
| TVO ILC, TVO Mathify | Toronto |
| TVO ILC, TVO Kids | Toronto |
| TVO ILC, TVO Learn | Toronto |
| TVO ILC | Toronto |
| Tyandaga Tennis Club | Burlington |
| Tyrsa Ukrainian Dance and Bandura School | Burlington |
