The Triple Nine Society (TNS) is an international high-IQ society for adults whose score on a standardized test demonstrates an IQ at or above the 99.9th percentile of the human population. The society recognizes scores from over 20 intelligence and academic aptitude tests.

Mensa International, whose members' test scores must land above the 98th percentile (or one in 50), may be the most popular, but it is just one option for the discerning test taker. The Triple Nine Society demands an IQ in the 99.9th percentile, whereas the Mega Society cuts off at the 99.9999th percentile (one in one million).