Does the spelling of a word mandatorily constrain spoken word production, or does it do so only when spelling is relevant for the production task at hand? Damian and Bowers (2003) reported spelling effects in spoken word production in English using a prompt-response word generation task. Preparation of the response words was disrupted when the responses shared initial phonemes that differed in spelling, suggesting that spelling constrains speech production mandatorily. The present experiments, conducted in Dutch, tested for spelling effects using word production tasks in which spelling was clearly relevant (oral reading in Experiment 1) or irrelevant (object naming and word generation in Experiments 2 and 3, respectively). Response preparation was disrupted by spelling inconsistency only with the word reading, suggesting that the spelling of a word constrains spoken word production in Dutch only when it is relevant for the word production task at hand.