10586 committees
| Name | Candidate | Type | Party | City | First Registered |
|---|---|---|---|---|---|
| OPERATING ENGINEERS | — | Political Action Committee | — | Hamden | Nov. 7, 2002 |
| Operating Engineers | — | Political Action Committee | — | Hamden | Oct. 31, 2005 |
| Operating Engineer Continuing PAC | — | Political Action Committee | — | Hamden | Feb. 11, 2002 |
| OO For CT | Olaleye Onikuyide | Candidate Committee | Democrat | West Hartford | Jan. 16, 2026 |
| One Windham | Lynne C. Ide | Political Action Committee | — | Willimantic | Jan. 8, 2002 |
| One Wallingford | — | Political Action Committee | — | Wallingford | Dec. 1, 2019 |
| One New London | Thomas P Lacey | Party Committee | One New London | New London | July 12, 2007 |
| One Bloomfield | Joseph M. Suggs | Political Action Committee | — | Bloomfield | May 30, 2003 |
| Ondusko For Norwich | Dianne G. Ondusko | Candidate Committee | Democrat | Norwich | Aug. 17, 2000 |
| On Target | Jason E Lebel | Political Action Committee | — | Wallingford | Dec. 17, 2020 |
| Olkin for Probate | Mathew R Olkin | Candidate Committee | Democrat | Willimantic | July 26, 2024 |
| Oliver for State Rep. | Mary A. Oliver | Candidate Committee | Democrat | Vernon | Jan. 28, 2002 |
| Oliveira 2006 | Christopher F. Oliveira | Exploratory Committee | — | Old Lyme | Jan. 2, 2006 |
| Olin Corporation Good Government Fund of Connecticut | William B. McDaniel | Political Action Committee | — | Norwalk | Jan. 1, 1998 |
| Olin Corporation Good Government Fund Of Connecticut | Dolores J Ennico | Political Action Committee | — | Wilton | Jan. 1, 1998 |
| Olga Anastos for State Representative | Olga Anastos | Candidate Committee | Republican | Stamford | Jan. 25, 2023 |
| Olga Anastos | Olga Anastos | Candidate Exemption Committee | Republican | Stamford | June 7, 2024 |
| Oldfield for Mayor | Jon Z Oldfield | Candidate Committee | Unaffiliated | Norwich | April 26, 2017 |
| Old Saybrook Women's Republican Club | — | Political Action Committee | Republican | Old Saybrook | Dec. 19, 2002 |
| Old Saybrook Republican Women's Club | Eileen C. Torrenti | Political Action Committee | Republican | Old Saybrook | July 22, 1999 |
| Old Saybrook Republican Town Committee | Margaret B. Viggiano | Party Committee | Republican | Old Saybrook | July 8, 1998 |
| Old Saybrook Democratic Town Committee | Deborah C Shah | Party Committee | Democrat | Old Saybrook | July 8, 1998 |
| Old Lyme Republican Town Committee | Diane Atwood Johnson | Party Committee | Republican | Old Lyme | July 8, 1998 |
| Old Lyme Democratic Town Committee | David B. Woolley | Party Committee | Democrat | South Lyme | July 8, 1998 |
| Ohler 2020 | Brian M Ohler | Candidate Committee | Republican | Canaan | May 11, 2020 |
| Ohler 2018 | Brian M Ohler | Candidate Committee | Republican | North Canaan | Jan. 12, 2018 |
| Ohler 2016 | Brian M Ohler | Candidate Committee | Republican | Canaan | May 4, 2016 |
| Odle 2012 | Dennis Odle | Candidate Committee | Republican | Waterbury | May 16, 2012 |
| Odegard for Senate | David O. Odegard | Candidate Committee | Republican | Glastonbury | July 29, 2002 |
| Obrien2010 | Melanie P O'Brien | Candidate Committee | Republican | Bethel | March 2, 2010 |
| Obrien 2008 | Melanie P O'Brien | Candidate Committee | Republican | Bethel | April 17, 2008 |
| Oberlander For Greenwich | Jill Oberlander | Candidate Committee | Democrat | Cos Cob | June 2, 2014 |
| Ob/Gyn Alliance Legislative Affairs Committee | Steven J. Fleischman | Political Action Committee | — | New Haven | Aug. 28, 2000 |
| O'neill For Senate | Arthur J. O'Neill | Candidate Committee | Republican | Southbury | Nov. 21, 2007 |
| O'neill Explore | Arthur J. O'Neill | Exploratory Committee | Republican | Southbury | Jan. 23, 2014 |
| O'dea For State Rep. | Thomas P. O'Dea | Candidate Committee | Republican | New Canaan | April 16, 2012 |
| O'Connor for Eastern Connecticut | — | Candidate Committee | Republican | Bozrah | July 26, 2002 |
| O'Connor 2004 | Brian J. O'Connor | Candidate Committee | Democrat | Westbrook | Feb. 2, 2004 |
| O'Connor 2002 | Brian J. O'Connor | Candidate Committee | Democrat | Westbrook | Jan. 25, 2002 |
| O'Connor 2000 | Brian J. O'Connor | Candidate Committee | Democrat | Westbrook | June 20, 2000 |
| O'Brien for the 115th | Edward M O'Brien | Candidate Committee | Democrat | West Haven | Dec. 21, 2023 |
| O'Brien for State Representative | Tim O'Brien | Candidate Committee | Democrat | New Britain | May 9, 2002 |
| O'brien For State Representative | Timothy O'Brien | Candidate Committee | Democrat | New Britain | Dec. 17, 2007 |
| O'Brien for State Represenatative | Tim O'Brien | Candidate Committee | Democrat | New Britain | Jan. 24, 2006 |
| O'Brien for New Milford | Thomas P O'Brien | Candidate Committee | Democrat | Brookfield | March 28, 2018 |
| Nystrom For Norwich 17 | Peter A Nystrom | Candidate Committee | Republican | Norwich | March 11, 2017 |
| Nystrom 2K | Peter A. Nystrom | Exploratory Committee | — | Norwich | Oct. 20, 1999 |
| Nystrom 2002 | Peter A. Nystrom | Exploratory Committee | — | Norwich | March 13, 2002 |
| Nystrom 2000 | Peter A. Nystrom | Candidate Committee | Republican | Norwich | June 12, 2000 |
| NWCT Young Democrats | Jeff A Eckert | Political Action Committee | — | Torrington | Sept. 19, 2017 |