To synthesize the evidence on the efficacy of ADHD teacher training interventions for teachers' ADHD knowledge and reducing pupils' ADHD-type behaviors. Six electronic databases were systematically searched up to 14/04/20. Meta-analyses were performed to pool standardized mean differences (SMD). 29 studies were included in the systematic review, and 22 meta-analyzed. SMD for teacher knowledge within subjects at post-test and follow-up was 1.96 (95% confidence interval = 1.48, 2.43) and ‒1.21 (-2.02, -0.41) respectively. Between subjects analyses at post-test showed SMD = 1.56 (0.52, 2.59), with insufficient data at follow-up. At post-test, SMD for pupils' behavior within and between subjects was 0.78 (0.37, 1.18), and 0.71 (-0.11, 1.52), respectively. Medium-to-high risk of bias was found in all but one study. ADHD teacher training programs may be effective in initially improving ADHD teachers' knowledge. There is inconsistent evidence for their efficacy to reduce students' ADHD-type behaviors.