| Index | Defiance | Missouri | National |
| Average Test Scores | n/a | 44% | 48% |
| Student/Teacher ratio | n/a | 14:1 | 16:1 |
| Total public schools | n/a | 1,899 | 79,221 |
| Total private schools | n/a | 531 | 24,874 |
| Total post-secondary schools | n/a | 213 | 7,963 |

| Index | Defiance | Missouri | National |
| Completed 8th grade | 91.1% | 86.0% | 84.3% |
| Completed high school | 91.1% | 84.2% | 83.0% |
| Completed some college | 53.6% | 57.7% | 59.4% |
| Completed associate degree | 25.9% | 35.2% | 38.5% |
| Completed bachelors | 17.9% | 27.6% | 30.3% |
| Completed masters | 0.0% | 10.4% | 11.5% |
| Completed professional degree | 0.0% | 2.8% | 3.3% |
| Completed doctorate | 0.0% | 1.2% | 1.3% |
There are a total of n/a public schools, n/a private schools and n/a post-secondary schools in Defiance. Using the proficiency score averages, the average test scores for Defiance, MO schools is n/a. The average student to teacher ratio is n/a. In Defiance, MO, an average of 91.1% of students have completed 8th grade and an average of 91.1% have completed high school.
| City | Population | Avg. Test Scores | National Avg. |
| Dardenne Prairie, MO | 13,884 | 73% | 51.0% |
| Lake St. Louis, MO | 16,749 | 71% | 48.4% |
| Weldon Spring, MO | 5,688 | 70% | 45.5% |
| Chesterfield, MO | 48,902 | 69% | 43.2% |
| Cottleville, MO | 5,566 | 69% | 43.1% |
| Defiance, MO | 70 | n/a |