| Bridgeport School District | Bridgeport | PK–12 | 20,022 |
| New Haven School District | New Haven | PK–12 | 18,817 |
| Waterbury School District | Waterbury | PK–12 | 18,776 |
| Hartford School District | Hartford | PK–12 | 16,434 |
| Stamford School District | Stamford | PK–12 | 16,185 |
| Danbury School District | Danbury | PK–12 | 11,956 |
| Norwalk School District | Norwalk | PK–12 | 11,473 |
| Connecticut Technical Education and Career System | Hartford | 9–12 | 11,296 |
| New Britain School District | New Britain | PK–12 | 10,038 |
| Fairfield School District | Fairfield | PK–12 | 9,139 |
| West Hartford School District | West Hartford | PK–12 | 9,128 |
| Capitol Region Education Council | Hartford | PK–12 | 9,091 |
| Meriden School District | Meriden | PK–12 | 8,707 |
| Greenwich School District | Greenwich | PK–12 | 8,465 |
| Bristol School District | Bristol | PK–12 | 7,713 |
| Trumbull School District | Trumbull | PK–12 | 6,943 |
| Stratford School District | Stratford | PK–12 | 6,578 |
| East Hartford School District | East Hartford | PK–12 | 6,504 |
| Southington School District | Southington | PK–12 | 6,200 |
| Manchester School District | Manchester | PK–12 | 6,122 |
| West Haven School District | West Haven | PK–12 | 5,950 |
| Glastonbury School District | Glastonbury | PK–12 | 5,696 |
| Hamden School District | Hamden | PK–12 | 5,464 |
| Westport School District | Westport | PK–12 | 5,281 |
| Wallingford School District | Wallingford | PK–12 | 5,241 |
| Milford School District | Milford | PK–12 | 5,218 |
| South Windsor School District | South Windsor | PK–12 | 5,125 |
| Enfield School District | Enfield | PK–12 | 4,694 |
| Darien School District | Darien | PK–12 | 4,673 |
| Shelton School District | Shelton | PK–12 | 4,518 |
| Ridgefield School District | Ridgefield | PK–12 | 4,484 |
| Middletown School District | Middletown | PK–12 | 4,394 |
| Cheshire School District | Cheshire | PK–12 | 4,317 |
| Farmington School District | Farmington | PK–12 | 4,195 |
| Simsbury School District | Simsbury | PK–12 | 4,127 |
| Naugatuck School District | Naugatuck | PK–12 | 4,095 |
| New Canaan School District | New Canaan | PK–12 | 4,060 |
| Groton School District | Mystic | PK–12 | 4,009 |
| Newtown School District | Newtown | PK–12 | 3,924 |
| Torrington School District | Torrington | PK–12 | 3,911 |
| Newington School District | Newington | PK–12 | 3,855 |
| Wilton School District | Wilton | PK–12 | 3,782 |
| New Milford School District | New Milford | PK–12 | 3,532 |
| Wethersfield School District | Wethersfield | PK–12 | 3,471 |
| Monroe School District | Monroe | PK–12 | 3,458 |
| Regional School District 15 | Middlebury | PK–12 | 3,368 |
| Norwich School District | Norwich | PK–12 | 3,291 |
| Windsor School District | Windsor | PK–12 | 3,266 |
| Vernon School District | Vernon | PK–12 | 3,236 |
| Bethel School District | Bethel | PK–12 | 3,227 |
| North Haven School District | North Haven | PK–12 | 3,214 |
| Windham School District | Willimantic | PK–12 | 3,153 |
| Avon School District | Avon | PK–12 | 3,092 |
| Guilford School District | Guilford | PK–12 | 3,080 |
| New London School District | New London | PK–12 | 2,918 |
| East Haven School District | East Haven | PK–12 | 2,857 |
| Berlin School District | Berlin | PK–12 | 2,634 |
| Branford School District | Branford | PK–12 | 2,567 |
| Brookfield School District | Brookfield | PK–12 | 2,542 |
| Rocky Hill School District | Rocky Hill | PK–12 | 2,539 |
| Watertown School District | Watertown | PK–12 | 2,528 |
| Ellington School District | Ellington | PK–12 | 2,526 |
| East Lyme School District | East Lyme | PK–12 | 2,500 |
| Madison School District | Madison | PK–12 | 2,445 |
| Ansonia School District | Ansonia | PK–12 | 2,404 |
| Killingly School District | Danielson | PK–12 | 2,392 |
| Ledyard School District | Ledyard | PK–12 | 2,347 |
| Waterford School District | Waterford | PK–12 | 2,281 |
| Plainville School District | Plainville | PK–12 | 2,223 |
| Tolland School District | Tolland | PK–12 | 2,144 |
| Regional School District 10 | Burlington | PK–12 | 2,140 |
| Regional School District 05 | Woodbridge | 7–12 | 2,138 |
| New Fairfield School District | New Fairfield | PK–12 | 2,123 |
| Seymour School District | Seymour | PK–12 | 2,103 |
| Colchester School District | Colchester | PK–12 | 2,101 |
| Weston School District | Weston | PK–12 | 2,101 |
| Wolcott School District | Wolcott | PK–12 | 2,100 |
| Norwich Free Academy District | Norwich | 9–12 | 2,097 |
| Suffield School District | Suffield | PK–12 | 2,027 |
| Montville School District | Oakdale | PK–12 | 2,001 |
| Regional School District 16 | Prospect | PK–12 | 1,898 |
| Bloomfield School District | Bloomfield | PK–12 | 1,897 |
| Plainfield School District | Plainfield | PK–12 | 1,886 |
| Cromwell School District | Cromwell | PK–12 | 1,841 |
| Griswold School District | Griswold | PK–12 | 1,823 |
| Area Cooperative Educational Services | North Haven | PK–12 | 1,726 |
| Stonington School District | Mystic | PK–12 | 1,722 |
| Regional School District 17 | Higganum | PK–12 | 1,716 |
| Granby School District | Granby | PK–12 | 1,709 |
| East Hampton School District | East Hampton | PK–12 | 1,676 |
| Oxford School District | Oxford | PK–12 | 1,622 |
| Regional School District 20 | Litchfield | PK–12 | 1,619 |
| Coventry School District | Coventry | PK–12 | 1,612 |
| Regional School District 14 | Woodbury | PK–12 | 1,561 |
| North Branford School District | Northford | PK–12 | 1,546 |
| Windsor Locks School District | Windsor Locks | PK–12 | 1,448 |
| Canton School District | Collinsville | PK–12 | 1,439 |
| Clinton School District | Clinton | PK–12 | 1,426 |
| Learn | Old Lyme | PK–12 | 1,390 |
| Somers School District | Somers | PK–12 | 1,347 |
| Regional School District 13 | Durham | PK–12 | 1,339 |
| Derby School District | Derby | PK–12 | 1,311 |
| Regional School District 18 | Old Lyme | PK–12 | 1,281 |
| Stafford School District | Stafford Springs | PK–12 | 1,266 |
| Orange School District | Orange | PK–6 | 1,254 |
| Portland School District | Portland | PK–12 | 1,250 |
| Plymouth School District | Terryville | PK–12 | 1,244 |
| Goodwin University Educational Services (gues) | East Hartford | PK–12 | 1,223 |
| Putnam School District | Putnam | PK–12 | 1,176 |
| Amistad Academy District | New Haven | K–12 | 1,105 |
| Achievement First Bridgeport Academy District | New Haven | K–12 | 1,090 |
| Regional School District 08 | Hebron | 7–12 | 1,075 |
| Regional School District 19 | Storrs | 9–12 | 1,061 |
| East Windsor School District | East Windsor | PK–12 | 1,035 |
| Old Saybrook School District | Old Saybrook | PK–12 | 1,030 |
| The Woodstock Academy District | Woodstock | 9–12 | 1,022 |
| Lebanon School District | Lebanon | PK–12 | 968 |
| Mansfield School District | Storrs | PK–8 | 966 |
| East Haddam School District | Moodus | PK–12 | 954 |
| Achievement First Hartford Academy District | New Haven | K–12 | 907 |
| Easton School District | Easton | PK–8 | 894 |
| East Granby School District | East Granby | PK–12 | 880 |
| Woodbridge School District | Woodbridge | PK–6 | 862 |
| Redding School District | Easton | PK–8 | 855 |
| Brooklyn School District | Brooklyn | PK–12 | 852 |
| Thompson School District | North Grosvenor Dale | PK–12 | 826 |
| Regional School District 07 | Winsted | 7–12 | 818 |
| Regional School District 12 | Washington Depot | PK–12 | 798 |
| Thomaston School District | Thomaston | PK–12 | 777 |
| Capital Preparatory Harbor School District | Bridgeport | K–12 | 775 |
| Elm City College Preparatory School District | New Haven | K–12 | 760 |
| Cooperative Educational Services | Trumbull | PK–12 | 757 |
| Woodstock School District | Woodstock | PK–11 | 756 |
| North Stonington School District | North Stonington | PK–12 | 726 |
| Regional School District 09 | Easton | 9–12 | 712 |
| Bolton School District | Bolton | PK–12 | 688 |
| Hebron School District | Hebron | PK–6 | 681 |
| Great Oaks Charter School District | Bridgeport | 6–12 | 662 |
| Regional School District 04 | Deep River | 7–12 | 646 |
| Winchester School District | Winsted | PK–12 | 599 |
| Westbrook School District | Westbrook | PK–12 | 592 |
| Jumoke Academy District | Hartford | PK–12 | 571 |
| Stamford Charter School for Excellence District | Stamford | PK–8 | 543 |
| Canterbury School District | Canterbury | PK–12 | 512 |
| Highville Charter School District | New Haven | PK–12 | 499 |
| Marlborough School District | Marlborough | PK–6 | 458 |
| The Gilbert School District | Winsted | 7–12 | 452 |
| Columbia School District | Columbia | PK–12 | 444 |
| Park City Prep Charter School District | Bridgeport | 4–8 | 434 |
| New Hartford School District | New Hartford | PK–6 | 433 |
| Preston School District | Preston | PK–12 | 432 |
| New Beginnings Inc Family Academy District | Bridgeport | PK–8 | 431 |
| Bethany School District | Bethany | PK–6 | 430 |
| Lisbon School District | Lisbon | PK–12 | 422 |
| Odyssey Community School District | Manchester | PK–8 | 410 |
| Booker T. Washington Academy District | New Haven | K–8 | 404 |
| Brass City Charter School District | Waterbury | PK–8 | 401 |
| Salem School District | Salem | PK–12 | 392 |
| Willington School District | Willington | PK–8 | 376 |
| Eastern Connecticut Regional Educational Service Center (eas | Hampton | 2–12 | 367 |
| Integrated Day Charter School District | Norwich | PK–8 | 364 |
| Regional School District 01 | Falls Village | 8–12 | 356 |
| Ashford School District | Ashford | PK–8 | 351 |
| Pomfret School District | Pomfret Center | PK–8 | 333 |
| Interdistrict School for Arts and Comm District | New London | 4–8 | 328 |
| Elm City Montessori School District | New Haven | PK–8 | 312 |
| Sterling School District | Sterling | PK–12 | 310 |
| Essex School District | Deep River | PK–6 | 308 |
| Salisbury School District | Lakeville | PK–8 | 288 |
| The Bridge Academy District | Bridgeport | 7–12 | 281 |
| Sprague School District | Baltic | PK–12 | 265 |
| Edadvance | Litchfield | 1–12 | 263 |
| North Canaan School District | Canaan | PK–8 | 245 |
| Andover School District | Andover | PK–6 | 239 |
| Side by Side Charter School District | Norwalk | PK–8 | 236 |
| Sherman School District | Sherman | PK–12 | 231 |
| Barkhamsted School District | Barkhamsted | PK–6 | 227 |
| Common Ground High School District | New Haven | 9–12 | 221 |
| Voluntown School District | Voluntown | PK–12 | 217 |
| Chester School District | Deep River | PK–6 | 198 |
| Regional School District 11 | Chaplin | 7–12 | 194 |
| Deep River School District | Deep River | PK–6 | 189 |
| Franklin School District | North Franklin | PK–11 | 188 |
| Bozrah School District | Bozrah | PK–8 | 180 |
| Kent School District | Kent | PK–8 | 180 |
| Eastford School District | Eastford | PK–8 | 173 |
| Chaplin School District | Chaplin | PK–6 | 150 |
| Unified School District #1 | Wethersfield | 9–12 | 145 |
| Hartland School District | East Hartland | PK–9 | 123 |
| Sharon School District | Sharon | PK–8 | 97 |
| Scotland School District | Scotland | PK–6 | 96 |
| Cornwall School District | Cornwall | PK–8 | 86 |
| Unified School District #2 | Hartford | K–12 | 80 |
| Explorations District | Winsted | 9–12 | 77 |
| Hampton School District | Hampton | PK–6 | 74 |
| Canaan School District | Falls Village | K–8 | 70 |
| Colebrook School District | Colebrook | K–6 | 61 |
| Norfolk School District | Norfolk | PK–6 | 61 |
| Union School District | Union | PK–8 | 49 |
| Department of Mental Health and Addiction Services | Hartford | 9–12 | 2 |
| Project Oceanology | Groton | — | — |
| Edmonds Cofield Preparatory Academy for Young Men Inc. Distr | New Haven | — | — |
| Litchfield School District | Litchfield | — | — |
| Shared Services | Winsted | — | — |
| Office of Early Childhood (oec) | Hartford | — | — |
| Office of Higher Education | Hartford | — | — |
| Department of Aging and Disability Services | Hartford | — | — |
| Regional School District 06 | Litchfield | — | — |
| Judicial Centers | Glastonbury | 5–12 | — |
| Department of Social Services | Hartford | — | — |