Purchase All 5 Full-Length OAT Practice Tests and Save $10!
The ADA has also constructed a free practice exam. This is a free pdf download of a test constructed by the ADA which contains useful practice material: free OAT test.
You may also consider taking a free DAT test from the ADA (just ignore the PAT section): free DAT test.
TopScore Pro for the OAT
3 updated full-length practice OAT tests
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Dr. Brett Ferdinand
2 updated full-length practice OAT tests