Many children are fussy or demanding about food, and managing these behaviors can be difficult and distressing for parents. Yet, no previous study had examined whether Parent-Child Interaction Therapy (PCIT), an interactive parenting support program that coaches caregivers while they interact with their young children, improves problematic mealtime behaviors and food-related parenting practices. In this study, 178 parents in Australia (Mage = 35.1 years, SD = 7.5 years; 93% female) of young children (Mage = 4.5 years, SD = 1.3, 76% male) completed up to two baseline surveys (prior to a waitlist, pre-PCIT) and a third survey after PCIT. The surveys included measures of their parenting practices in general and related to feeding and mealtimes, beliefs about eating, and children's mealtime behavior (e.g., food avoidance, mealtime aggression) and general externalizing symptoms. Using paired t-tests, no changes were found during baseline (pre-waitlist to pre-PCIT), but from pre- to post-PCIT, medium to large improvements were found in parent mealtime demandingness and responsiveness, aversion to mealtime, child eating behaviors, general parenting practices, and child externalizing behavior. However, positive mealtime environment did not improve and improvements in general parenting and behavior were larger than for eating-related parenting and child behavior. The findings suggest that PCIT can be effective for reducing most problematic mealtime behaviors and can improve multiple parental feeding practices.