Teachers play an important role in the diagnosis and management of Attention Deficit Hyperactivity Disorder (ADHD). There are no published studies on Indian teachers' knowledge of ADHD. In the present study, the aim was to assess knowledge and misperceptions about ADHD among schoolteachers in Mumbai. A total of 106 teachers from 12 English-medium schools completed the Knowledge of Attention Deficit Disorders Scale and a demographic questionnaire. Overall, the teachers lacked adequate knowledge of ADHD, with only 49% of the responses being correct. Repeated measures ANOVA results indicated that the teachers' scores on the three subscales of the measure were significantly different (F = 7.96, p < 0.01), with the score being highest on the symptoms subscale. In conclusion, teachers in Mumbai need training on general information and treatment of ADHD, with a focus on correcting common misperceptions that they have with regards to ADHD.