The activities of the n‐C1through n‐C10esters of 2,3‐dichlorobenzoic acid (DCBA) were tested as inhibitors of terminal growth of Xanthi‐nc tobacco plants. The C2and C3esters were the most active as emulsions at 2.5 × 10–2m. They retarded growth of the entire bud for 10 days and longer upon repeated applications. Treatment of plants with 2,3‐DCBA or its potassium salt at dosages up to 5 × 10–2mcaused only slight growth regulating effects. In a dosage‐response study, it was clearly shown that the C3ester inhibited stem elongation but the C8ester did not. The striking differences in plant growth due to treatment with 2,3‐DCBA esters of different alkyl chain lengths are discussed in terms of penetration, ester hydrolysis, and growth factor interactions.