Background/Objective: Given the negative consequences of weight bias, including internalized weight stigma, on health outcomes, two instruments—the Weight Self-Stigma Questionnaire (WSSQ) and Weight Bias Internalization Scale (WBIS)—have been developed. However, their psychometric properties are yet to be tested for Asian pediatric populations.

Method: Participants aged 8 to 12 years (N = 287; 153 boys) completed the WSSQ and the WBIS, and they were classified into either a group with overweight or a group without overweight based on self-reported weight and height.

Results: Both WSSQ and WBIS had their factor structures supported by confirmatory factor analyses (CFAs). The measurement invariance of two-factor structure was further supported for WSSQ across gender and weight status. The measurement invariance of single-factor structure was supported for WBIS across gender but not across weight status.

Conclusions: WSSQ and WBIS were both valid to assess the internalization of weight bias. However, the two instruments demonstrated different properties and should be applied in different situations.