Using an innovative method, a Single-Target Implicit Association Test (ST-IAT) was created to explore the implicit theories of intelligence among science and liberal arts teachers and their relationships with their gender. The results showed that for science teachers--especially for male teachers--there was a negative implicit association between "intelligence" and "modifiable" stimuli, whereas liberal arts teachers had no implicit association between these two variables. The results are discussed in comparison with previous explicit measures, and the implications for teacher training are highlighted.