| OBAMA SERVICE LEARNING ELEMENTARY | 135 | regular | other |
| Ober D'Vorre & Hal ES | 536 | regular | other |
| Oberle (William) Elementary School | 512 | regular | elementary |
| Oberlin Elem | 232 | regular | other |
| Oberlin Elementary School | 262 | regular | other |
| Oberlin Elementary School | 356 | regular | other |
| Oberlin High School | 180 | regular | other |
| Oberlin High School | 218 | regular | high |
| Oberlin Middle | 1,049 | regular | middle |
| OBERON ELEMENTARY SCHOOL | 52 | regular | elementary |
| Oberon Middle School | 704 | regular | middle |
| Obion County Central High School | 652 | regular | high |
| Oblong Elem School | 361 | regular | other |
| Oblong High School | 165 | regular | high |
| Obsidian Middle School | 568 | regular | middle |
| OBUCH MS | 207 | regular | middle |
| OCALA CENTER FOR SUCCESS AND INDEPENDENCE | 64 | alternative | other |
| Ocala Middle | 377 | regular | middle |
| OCALA SPRINGS ELEMENTARY SCHOOL | 682 | regular | other |
| OCALI CHARTER MIDDLE SCHOOL | 194 | regular | middle |
| OCASA College Prep | 83 | regular | other |
| Occohannock Elementary | 385 | regular | other |
| Occoquan Elementary | 571 | regular | elementary |
| OCCS:CHEP/PCHS | 290 | alternative | other |
| OCEAN | 144 | alternative | other |
| Ocean Academy | 150 | special-ed | other |
| Ocean Academy Charter School | 551 | regular | elementary |
| Ocean Acres Elementary School | 747 | regular | other |
| Ocean Air | 450 | regular | elementary |
| Ocean Alternative Education Center | 76 | regular | elementary |
| Ocean Avenue | 337 | regular | elementary |
| Ocean Avenue Elementary School | 283 | regular | other |
| OCEAN AVENUE SCHOOL | 346 | regular | elementary |
| Ocean Bay Elementary | 1,181 | regular | other |
| Ocean Bay Middle | 801 | regular | middle |
| Ocean Beach Early Childhood Center | 24 | regular | other |
| Ocean Beach Elementary | 432 | regular | elementary |
| Ocean Beach Options Academy | 56 | alternative | other |
| OCEAN BREEZE ELEMENTARY SCHOOL | 498 | regular | other |
| Ocean Charter | 563 | regular | elementary |
| Ocean City Elementary | 566 | regular | other |
| Ocean City High School | 1,106 | regular | high |
| Ocean City Intermediate School | 326 | regular | elementary |
| Ocean City Primary School | 271 | regular | other |
| Ocean County Vocational Technical School Brick Center | 2 | vocational | high |
| Ocean County Vocational Technical School Jackson Center | 2 | vocational | high |
| Ocean County Vocational Technical School Toms River Center | 1 | vocational | high |
| Ocean County Vocational Technical School Waretown Center | 74 | vocational | high |
| Ocean Crest Elementary School | 240 | regular | elementary |
| Ocean Drive Elementary | 852 | regular | other |