Children's vegetable intake is in general below recommendations. It is known that self-selection of vegetables out of multiple options can increase intake in children. However, it is not clear if this effect is driven by a pre-existing preference for the selected food, or purely by having a choice. Allowing children to choose could create a positive bias and endorse feelings of autonomy, which could increase acceptance of the food and promote intake. The aim of the present pre-registered study was to investigate the effect of choice in promoting the acceptance of an unfamiliar vegetable during a blind-choice task. Children aged 4–5 years old (n = 161) were randomly assigned to the choice or no-choice condition. Each child was presented with three closed cups, containing a vegetable. The children were unaware that the cups contained the same vegetable, a piece of raw celeriac. In the choice condition, the children were able to choose a cup themselves whereas in the no-choice condition, the experimenter made the decision. We hypothesized that children in the choice condition would show more acceptance of the vegetable compared to children in the no-choice condition and that higher levels of picky eating would lead to less vegetable acceptance. The results demonstrated that choice indeed significantly increased vegetable acceptance (4.7 ± 1.7 versus 4.0 ± 1.9 on a 6-point scale), irrespective of pickiness in eating. In addition, picky children showed less acceptance of the vegetable compared to non-picky children. The results of this study imply that choice is an important factor in promoting unfamiliar vegetable intake in young children. Including children in the decision process may be a practical strategy for educators and caregivers to increase children's vegetable intake.