Theory of mind (ToM) refers to the ability to reason about the behaviour of others and oneself by attributing internal mental states, such as knowledge, desires and intentions. ToM can be applied recursively - for example, “Amy thinks that Bernard knows that it is raining” is said to be a second-order ToM statement from the reader's perspective. Past research suggests that there is a limit to the number of times humans can apply ToM recursively - for example, they tend to use up to second-order ToM reasoning in strategic games. In the present study, we propose and conduct a novel human experimental design, in which different orders of ToM reasoning in the logic puzzle “Cheryl’s Birthday” can be distinguished. Results show that higher-order ToM reasoning is associated with longer times to solve the puzzle(s) and a higher rate of mistakes.