Forestry officials and police, following a tip-off, searched the school in Mae Hong Son's Mae Sariang district, and confiscated the wood.
The evidence was sent to local police to probe and make arrests later, he said.
Police would summon the school director, who went on a civil service errand to Muang district, for testimony, he said.
Teak wood trees in the school area had been cut down, processed and then hidden from sight, he said.