| Shalom Village | Other Public Sector Employers | 2015 | 6 | $113,576 |
| Shalom Village Home for the Aged | Other Public Sector Employers | 2016 | 2 | $128,764 |
| Shalom Village Long-Term Care | Other Public Sector Employers | 2025 | 11 | $127,466 |
| Sharbot Lake Family Health Team | Other Public Sector Employers | 2023 | 1 | $122,648 |
| Shared Support Services Southeastern Ontario | Other Public Sector Employers | 2010 | 5 | $128,934 |
| Shaver Hospital | Hospitals & Boards of Public Health | 1998 | 1 | $101,049 |
| Sheeo Canada Fund | Other Public Sector Employers | 2018 | 1 | $168,837 |
| Sheet Metal Workers' Int'l Assoc | Other Public Sector Employers | 2018 | 2 | $117,814 |
| Sheet Metal Workers' Int'l Assoc Loc 285 Training Trust Fnd | Other Public Sector Employers | 2010 | 1 | $120,311 |
| Sheet Metal Workers' International Association Local 285 Training Centre | Other Public Sector Employers | 2025 | 4 | $160,638 |
| Sheet Metal Workers’ International Association Local Union 285 Training Centre | Other Public Sector Employers | 2013 | 1 | $130,585 |
| Shepherd Village Inc | Other Public Sector Employers | 2025 | 20 | $149,352 |
| Shepherds of Good Hope | Other Public Sector Employers | 2025 | 5 | $124,047 |
| Sherbourne Health Centre | Other Public Sector Employers | 2025 | 18 | $131,598 |
| Sheridan | Colleges | 1997 | 3 | $108,614 |
| Sheridan College Institute of Technology and Advanced Learning | Colleges | 2025 | 789 | $130,221 |
| Sheridan College of Applied Arts and Technology | Colleges | 1996 | 3 | $113,967 |
| Sherwood Park Manor | Other Public Sector Employers | 2025 | 9 | $125,140 |
| Sheshegwaning First Nation | Other Public Sector Employers | 2024 | 2 | $107,781 |
| Shingwauk Teaching Lodge | Other Public Sector Employers | 2025 | 2 | $181,538 |
| Shkagamik-Kwe Health Centre | Other Public Sector Employers | 2025 | 12 | $146,430 |
| Shkagamik–Kwe Health Centre | Other Public Sector Employers | 2012 | 2 | $105,016 |
| Shkoday Abinojiiwak Obimiwedoon | Other Public Sector Employers | 2025 | 1 | $100,422 |
| SickKids Centre for Community Mental Health | Other Public Sector Employers | 2025 | 15 | $135,102 |
| Silent Voice Canada Inc | Other Public Sector Employers | 2025 | 1 | $107,593 |
| SIM-one Ontario Simulation Network | Other Public Sector Employers | 2014 | 1 | $151,251 |
| Simcoe Community Services | Other Public Sector Employers | 2019 | 4 | $129,357 |
| Simcoe County | Municipalities & Services | 2002 | 2 | $114,285 |
| Simcoe County BE | School Boards | 1997 | 2 | $122,705 |
| Simcoe County Board of Education | School Boards | 1996 | 4 | $114,316 |
| Simcoe County District Health Unit | Hospitals & Boards of Public Health | 2004 | 1 | $210,441 |
| Simcoe County District School Board | School Boards | 2025 | 2,733 | $120,182 |
| Simcoe County RCSSB | School Boards | 1997 | 3 | $110,188 |
| Simcoe Muskoka Catholic District School Board | School Boards | 2025 | 1,095 | $122,338 |
| Simcoe Muskoka Child, Youth and Family Services | Other Public Sector Employers | 2025 | 61 | $125,834 |
| Simcoe Muskoka District Health Unit | Hospitals & Boards of Public Health | 2025 | 65 | $128,398 |
| Simcoe York DHC | Other Public Sector Employers | 2003 | 1 | $119,000 |
| Simcoe York District Health Council | Other Public Sector Employers | 2002 | 1 | $111,187 |
| Sinai Health System | Hospitals & Boards of Public Health | 2025 | 1,654 | $132,568 |
| Sioux Lookout First Nations Health Authority | Other Public Sector Employers | 2017 | 2 | $106,806 |
| Sioux Lookout Friendship Accord | Other Public Sector Employers | 2025 | 1 | $205,624 |
| Sioux Lookout Meno Ya Win Health Centre | Hospitals & Boards of Public Health | 2025 | 70 | $125,441 |
| Sioux Lookout Meno-Ya-Win HC | Hospitals & Boards of Public Health | 2004 | 3 | $118,630 |
| Sioux-Hudson Literacy Council | Other Public Sector Employers | 2025 | 1 | $105,432 |
| SiouxLookout Meno-Ya-Win Hth Ctr. | Hospitals & Boards of Public Health | 2002 | 2 | $101,272 |
| Sir Sandford Fleming of Applied Arts and Technology | Colleges | 2025 | 250 | $132,740 |
| Sistering – A Woman's Place | Other Public Sector Employers | 2025 | 3 | $123,770 |
| Sisters of Charity Ottawa Health Serv | Hospitals & Boards of Public Health | 1998 | 7 | $133,017 |
| Sisters of St. Joseph for the Diocese of Toronto, in Upper Canada - St. Joseph's Infirmary & Private Hospital | Other Public Sector Employers | 2013 | 1 | $123,757 |
| Six Nations Elected Council - Justice Program | Other Public Sector Employers | 2018 | 2 | $108,351 |
| Six Nations of the Grand River | Other Public Sector Employers | 2020 | 6 | $127,424 |
| Six Nations Polytechnic Inc | Other Public Sector Employers | 2025 | 6 | $106,908 |
| Skate Canada | Other Public Sector Employers | 2014 | 9 | $148,760 |
| Skate Ontario | Other Public Sector Employers | 2022 | 3 | $144,502 |
| Skilled Trades Ontario | Crown Agencies | 2025 | 42 | $136,592 |
| Skills / Competences Canada - Ontario | Other Public Sector Employers | 2016 | 1 | $116,257 |
| Skills Canada Ontario | Other Public Sector Employers | 2025 | 6 | $150,376 |
| Skills for Change | Other Public Sector Employers | 2015 | 1 | $115,000 |
| Skills for Change of Metro Toronto | Other Public Sector Employers | 2025 | 8 | $137,221 |
| Skills/Competences Canada - Ontario | Other Public Sector Employers | 2015 | 1 | $120,728 |
| Skylark Children Youth and Families | Other Public Sector Employers | 2019 | 8 | $117,401 |
| Slate Falls First Nation | Other Public Sector Employers | 2021 | 2 | $128,604 |
| Slovenian Linden Foundation | Other Public Sector Employers | 2025 | 6 | $113,642 |
| Slt.Ste.Marie & Dist.Grp.Hlth Assoc. | Other Public Sector Employers | 2001 | 1 | $139,751 |
| Small Business & Consumer Services | Government of Ontario – Ministries | 2008 | 25 | $126,594 |
| Small Business & Entrepreneurship | Government of Ontario – Ministries | 2007 | 9 | $116,712 |
| Smart Local 47 Training Centre Inc | Other Public Sector Employers | 2025 | 2 | $144,326 |
| Smart Risk Foundation | Other Public Sector Employers | 2009 | 2 | $143,600 |
| Smiths Falls Nurse Pracititioner Led Clinic | Other Public Sector Employers | 2023 | 2 | $127,178 |
| Smithville Family Health Team | Other Public Sector Employers | 2023 | 2 | $128,206 |
| Smoking and Health Action Foundation | Other Public Sector Employers | 2015 | 1 | $100,470 |
| SMOL - St. Mary's | Hospitals & Boards of Public Health | 2002 | 1 | $106,806 |
| Smooth Rock Falls | Hospitals & Boards of Public Health | 2002 | 1 | $109,971 |
| Smooth Rock Falls Hospital | Hospitals & Boards of Public Health | 2025 | 23 | $137,278 |
| Smooth Rock Falls Hospital Corporation | Hospitals & Boards of Public Health | 2010 | 2 | $132,735 |
| SMWIA Local Union 285 Training Trust Fund | Other Public Sector Employers | 2016 | 1 | $140,529 |
| Soar Community Services | Other Public Sector Employers | 2025 | 5 | $116,586 |
| Social Benefits Tribuna, Child and Family Services Review Board and Custody Review Board | Crown Agencies | 2016 | 1 | $121,416 |
| Social Benefits Tribunal | Crown Agencies | 2023 | 14 | $125,698 |
| Social Benefits Tribunal/SARB | Crown Agencies | 2002 | 1 | $145,581 |
| Social Enterprise for Canada | Other Public Sector Employers | 2017 | 1 | $143,081 |
| Social Housing Services Corp. | Other Public Sector Employers | 2004 | 2 | $121,326 |
| Social Housing Services Corporation | Other Public Sector Employers | 2009 | 9 | $124,209 |
| Social Research and Demonstration Corporation (SRDC) | Other Public Sector Employers | 2016 | 11 | $134,105 |
| Social Service Bureau of Sarnia – Lambton Incorporated | Other Public Sector Employers | 2025 | 3 | $131,920 |
| Social Service Bureau of Sarnia-Lambton Incorporated Inc. | Other Public Sector Employers | 2013 | 1 | $122,668 |
| Social Service Bureau of Sarnia–Lambton Incorporated | Other Public Sector Employers | 2012 | 1 | $112,969 |
| Social Srvcs Admin Brd. - Cochrane | Other Public Sector Employers | 2003 | 1 | $104,399 |
| Social Srvcs Admin Brd. - Nipissing | Other Public Sector Employers | 2003 | 1 | $108,661 |
| Social Srvcs Admin Brd. - Parry Sound | Other Public Sector Employers | 2003 | 1 | $106,005 |
| Society of St Vincent de Paul Toronto Central Council | Other Public Sector Employers | 2025 | 1 | $109,974 |
| Softech Alliance Network | Other Public Sector Employers | 2016 | 1 | $105,000 |
| Softech Alliance Network (o/p Wetch Alliance) | Other Public Sector Employers | 2025 | 1 | $171,115 |
| Soldiers' Memorial | Hospitals & Boards of Public Health | 2002 | 4 | $134,358 |
| Solicitor General | Government of Ontario – Ministries | 2025 | 5,958 | $131,360 |
| Solicitor General & Correctional Svcs | Government of Ontario – Ministries | 1998 | 44 | $130,881 |
| Somerset West Comm. Health Cent. | Other Public Sector Employers | 1998 | 2 | $121,179 |
| Somerset West Community Health Centre | Other Public Sector Employers | 2025 | 18 | $164,400 |
| Somerset West Community Hlth Ctr. | Other Public Sector Employers | 1999 | 4 | $121,582 |
| Sound Times Support Services | Other Public Sector Employers | 2024 | 1 | $131,830 |