| | Organization Name(s) | Located In |
 | Habitat for Humanity Niagara | St Catharines |
 | Habitat for Humanity Niagara, ReStore | St Catharines |
 | Hamilton Health Sciences, Chedoke Hospital | Hamilton Mountain West |
 | Hamilton Health Sciences, Hamilton General Hospital, Pain Management Centre | Hamilton East |
 | Hamilton Health Sciences, McMaster Childrens Hospital, Pediatric Eating Disorders Program | Hamilton West |
 | Hamilton Health Sciences, McMaster Children's Hospital | Hamilton West |
 | Hamilton Health Sciences, McMaster University Medical Centre | Hamilton West |
 | Hamilton Health Sciences, Sexual Assault / Domestic Violence Care Centre, Hamilton General Hospital Location | Hamilton East |
 | Hamilton Health Sciences, Sexual Assault / Domestic Violence Care Centre, Juravinski Hospital Location | Hamilton Mountain East |
 | Hamilton Health Sciences, Sexual Assault / Domestic Violence Care Centre, McMaster Children's Hospital Location | Hamilton West |
 | Hamilton Health Sciences, St Peters Hospital, Centre for Healthy Aging, Geriatric Psychiatry and Medicine | Hamilton East |
 | Hamilton Health Sciences, St Peters Hospital, Community Services Programs, OTs2GO | Hamilton East |
 | Hamilton Niagara Haldimand Brant Hospice Palliative Care Network | St Catharines |
 | Hamilton Niagara Haldimand Brant Local Health Integration Network | Grimsby |
 | Hamilton. Hamilton Entertainment and Convention Facilities Incorporated, Hamilton Place | Hamilton Central |
 | Hamilton. Hamilton Entertainment and Convention Facilities Incorporated, Victor K Copps Trade Centre and Arena | Hamilton Central |
 | Hannah House Maternity Home | Niagara Falls |
| | Harmony Transport Services | St Catharines |
 | HATS - Horse Alternative Therapeutic Services | Pelham |
 | Hayakawa Kendo Club | Welland |
 | Head Injury Association of Fort Erie and District | Fort Erie |
 | Healthy from the Start, Canada Prenatal Nutrition Program (CPNP), Fort Erie | Fort Erie |
 | Healthy from the Start, Canada Prenatal Nutrition Program (CPNP), Niagara Falls | Niagara Falls |
 | Healthy from the Start, Canada Prenatal Nutrition Program (CPNP), Port Colborne | Port Colborne |
 | Healthy from the Start, Canada Prenatal Nutrition Program (CPNP), St Catharines | St Catharines |
 | Healthy from the Start, Canada Prenatal Nutrition Program (CPNP), Welland | Welland |
 | Healthy Living Niagara | St Catharines |
 | Heart and Stroke Foundation of Ontario | St Catharines |
 | Heart Niagara Inc | Niagara Falls |
 | Heartland Forest Nature Experience | Niagara Falls |
 | HeartSpace Physical Therapy for Children | St Catharines |
 | Heatherwood Retirement Residence, The | St Catharines |
 | Heidehof | St Catharines |
 | Heidehof, Edelweiss Seniors' Apartments | St Catharines |
 | Heidehof, Lindenhaus Seniors Life Lease Apartments | St Catharines |
 | Help a Child Smile | Welland |
| | Helping Hands Maid Service, Helping Hands Home Care | St Catharines |
 | Heritage Niagara | St Catharines |
 | Heritage Reformed Congregation | Jordan Station |
| | Herrington Group Ltd, The | St Catharines |
| | Historical Automobile Society of Canada | St Catharines |
| | Historical Society of St Catharines | St Catharines |
 | Holy Face of Jesus, Society of St Pius X | St Catharines |
 | Holy Ghost Slovak Greek Catholic Church | Welland |
 | Holy Trinity Anglican Church | Welland |
 | Holy Trinity Anglican Church, Chippawa | Niagara Falls |
| | Homewell Senior Care, Niagara Region | Beamsville |
 | Homewood Health Centre | Guelph-Eramosa |
| | Honeymoon City Toastmasters | Niagara Falls |
| | HOPE (Helping Others Parent Effectively), St Catharines | St Catharines |
 | Hope Air | Toronto (City of) |
 | Hope Centre, The | Welland |
 | Hope Centre, The, Hope House, Welland Emergency Hostel | Welland |
 | Hospice Niagara, The Stabler Centre | St Catharines |
 | Hospice Niagara, The Stabler Centre, Bereavement Support Group | St Catharines |
 | Hostelling International - St-Lawrence Region, HI-Niagara Falls Hostel | Niagara Falls |
 | Hotel Dieu Shaver Health & Rehabilitation Foundation | St Catharines |
 | Hotel Dieu Shaver Health and Rehabilitation Centre, Complex Care and Regional Rehabilitation | St Catharines |
 | Hotel Dieu Shaver Health and Rehabilitation Centre, Geriatric Rehabilitation Program | St Catharines |
 | Hotel Dieu Shaver Health and Rehabilitation Centre, NetWork Niagara | St Catharines |
 | Howell Family Pumpkin Farm | Fonthill |
 | Hub, The | Port Colborne |
| | Human Resources Professionals Association of Niagara | Fonthill |
| | Huntington Society of Canada, Niagara Chapter | Niagara Region |