In the current study we examine the influence of child individual differences on children's and adults' behaviours in unstructured forensic interviews. Thirty-eight interviews conducted by actual forensic interviewers with 3- to 7-year-old children were analysed for child reporting behaviours (assent, denial, acquiescence, accurate and inaccurate details, verbosity and cooperation) and adult behaviours (leading vs. neutral questions). Consistent with our predictions, child individual differences that were visible (marked, e.g. sociability) more often predicted child and adult behaviours than those that were not as apparent (unmarked, e.g. source monitoring). In addition to direct influences of the child individual differences on child behaviours, for some variables the influence of the child individual difference was mediated by differential responses by an interviewer (i.e. indirect effects) which then, in turn, influence the child. The ability to examine indirect influences by using unstructured interviews is emphasized. Copyright © 2004 John Wiley & Sons, Ltd.