["Psycho-Oncology, Volume 35, Issue 6, June 2026. ", "\nABSTRACT\n\nPurpose\nFear of progression (FoP) represents a significant psychological burden for pediatric cancer patients and their parents. This study investigates FoP levels across acute treatment (AcT) and follow‐up care (FuC) and examines trajectories over time, associated sociodemographic factors, and parent‐child associations. It also proposes clinically relevant thresholds for psychosocial care.\n\n\nMethods\nA total of 171 patient–parent dyads participated in a cross‐sectional and longitudinal study. Children aged 7–18 and one parent per child completed the Fear of Progression Questionnaire—Short Form (FoP‐Q‐SF). Data were collected during AcT (two time points) and FuC. Statistical analyses included nonparametric tests and correlation analyses.\n\n\nResults\nFoP levels were significantly lower during FuC compared to AcT for both children and parents, and parental FoP decreased over the 1‐year follow‐up period. Parents consistently showed higher FoP than their children, and a significant parent–child correlation emerged in FuC. FoP was higher in girls and was positively associated with child age and negatively associated with parent age. Using suggested thresholds, 57.8% of parents showed dysfunctional FoP. Among children, 45.2% reported low, 40% moderate, and 14.8% high FoP.\n\n\nConclusion\nAlthough levels of FoP are lower in FuC than in AcT, they remain a prevalent burden—particularly for younger parents, older children, and girls. The observed parent‐child associations highlight the need for family‐oriented psychosocial care. A proposed three‐stage cut‐off (low, moderate, high FoP) may guide clinical decision‐making and support tailored treatment strategies. Routine screening and preventive approaches are recommended to mitigate FoP and its potential intergenerational transmission.\n\n\nTrial Registration\nThe study has been pre‐registered at the German Clinical Trials Register (DRKS 00022034, registered 29th of June 2020) and at the Open Science Foundation (https://osf.io/fuahc).\n\n"]