| Index | O'Fallon | Missouri | National |
| Average Test Scores | 61% | 44% | 48% |
| Student/Teacher ratio | 17:1 | 14:1 | 16:1 |
| Total public schools | 16 | 1,899 | 79,221 |
| Total private schools | 4 | 531 | 24,874 |
| Total post-secondary schools | 1 | 213 | 7,963 |
| Index | O'Fallon | Missouri | National |
| Completed 8th grade | 92.8% | 86.0% | 84.3% |
| Completed high school | 92.0% | 84.2% | 83.0% |
| Completed some college | 70.7% | 57.7% | 59.4% |
| Completed associate degree | 46.5% | 35.2% | 38.5% |
| Completed bachelors | 38.6% | 27.6% | 30.3% |
| Completed masters | 13.5% | 10.4% | 11.5% |
| Completed professional degree | 1.9% | 2.8% | 3.3% |
| Completed doctorate | 0.9% | 1.2% | 1.3% |
There are a total of 16 public schools, 4 private schools and 1 post-secondary schools in O'Fallon. Using the proficiency score averages, the average test scores for O'Fallon, MO schools is 61%. The average student to teacher ratio is 17:1. In O'Fallon, MO, an average of 92.8% of students have completed 8th grade and an average of 92.0% have completed high school.
| City | Population | Avg. Test Scores | National Avg. |
| Dardenne Prairie, MO | 13,385 | 73% | 51.0% |
| Lake St. Louis, MO | 16,357 | 71% | 48.4% |
| Weldon Spring, MO | 5,536 | 70% | 45.5% |
| Chesterfield, MO | 47,603 | 69% | 43.2% |
| Cottleville, MO | 5,439 | 69% | 43.1% |
| O'Fallon, MO | 88,132 | 61% | 27.1% |
| City | Population | Avg. Test Scores | National Avg. |
| Palm Coast, FL | 88,222 | 61% | 26.0% |
| Champaign, IL | 88,288 | 32% | 33.7% |
| Newton, MA | 88,322 | 73% | 52.5% |
| Reading, PA | 88,333 | 31% | 35.8% |
| Conroe, TX | 88,369 | 46% | 4.0% |
| O'Fallon, MO | 88,132 | 61% | 27.1% |
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