PURPOSE: Posterior fossa tumour (PFT) surgery carries a risk of mutism or severely reduced speech. As for higher-cognitive language functions, word-finding difficulties have been reported, but no study has compared pre- and postoperative word-finding speeds to identify impairment caused by surgery. The current study investigated changes in word-finding ability associated with PFT surgery and examined factors affecting postoperative ability. METHOD: We included 184 children aged 5:0-17:9 years undergoing PFT surgery and assessed word-finding ability before and after surgery using a speeded picture-naming test. We compared postoperative word-finding performance with both preoperative performance and age-specific norms and examined factors affecting word-finding ability. RESULTS: We found no significant difference between pre- and postoperative performance, reflecting that some children exhibited better word-finding ability after surgery, others poorer. After surgery, 95% of the children performed two standard deviations above (slower than) age-specific norms. Tumour location in the fourth ventricle negatively affected postoperative word-finding ability (B = -4.09, p <
0.05). CONCLUSION: For some children, PFT surgery leads to postoperative word-finding difficulties, emphasizing the importance of postoperative language assessments and interventions. Fourth-ventricle tumour location emerged as a risk factor for poorer postoperative word-finding ability, likely reflecting surgical damage to the dentato-thalamo-cortical pathway (DTCP).