Obtaining accurate estimates of children’s dietary intake is important because these estimates are used to characterize diet-disease relationships and inform nutrition interventions. This systematic review synthesized findings from validation studies of dietary assessment tools for children (aged 1-10 years), in which parents were proxy-reporters. Database searches (Ovid Medline, Embase, Web of Science, Cochrane) in January 2026 for validation studies of dietary assessment tools used for estimating daily intake of macronutrients and micronutrients yielded 4,545 citations. Articles were uploaded to Covidence for screening. Sixty-six articles met the inclusion criteria. Median sample size was 103. Eighty-six percent of studies (n=57) validated a food frequency questionnaire; the remainder validated dietary recalls (11%, n=8) or food diaries (2%, n=1). Many studies (67%, n=44) used another parent-proxy report tool as the reference method. For most nutrients, over a quarter of the 66 studies failed to find a significant correlation between the assessment tool and reference method. Among the 69% of analyses that did show a significant correlation, the median correlation for each nutrient ranged from 0.37 to 0.40 for macronutrients and 0.29 to 0.55 for micronutrients. Studies were limited by lack of generalizability, use of reference methods prone to error, and misalignment between the assessment tool and reference method. Overall, this review found no correlation or low-to-moderate correlations between dietary assessments and the reference method. The studies had significant methodological limitations. Future studies should validate parent-proxy report dietary assessments against objective measures, such as biomarkers. The development of novel assessment tools may also be warranted.