Background and Objective: A balance ratio of dietary omega-3 (n-3) and omega-6 (n-6) fatty acids reduces childhood obesity. However, few studies have focused on validation of semiquantitative food frequency ques- tionnaire (SFFQ) for determining the n-3 and n-6 intakes in children. Therefore, a valid SFFQ for assessing n-3 and n-6 intakes among Indonesian children is required. Methods and Study Design: A cross-sectional study was conducted by selecting 89 healthy children through multistage random sampling. Dietary intakes were assessed using the SFFQ and a 3-day non-consecutive 24-h recall. Randomly selected children (n=35) were assessed for plasma phospholipid fatty acid (PFA). In total, 78 food items in the SFFQ, as in the Thai, Vietnamese, and American food composition databases, were validated using dietary recall and PFA. The SFFQ was readminis- tered after 4 weeks to assess its reproducibility. The validity and reproducibility of the SFFQ were determined by Bland–Altman analysis. Results: Favourable agreement was found between the SFFQ and recall for docosahexa- noic acid, eicosapentanoic acid, docosapentanoic acid, and arachidonic acid, but not for total n-3, n-6, α-linolenic acid, or linoleic acid. Significant correlations were found between the SFFQ estimations and plasma n-6 and LA (r=0.40, p=0.025; and r=0.42, p=0.018, respectively). A 95% limit of Bland–Altman agreement was observed be- tween the first and repeat SFFQ for all fatty acids. Conclusion: The proposed SFFQ is sufficiently valid and reli- able for assessment of essential fatty acids intakes in Indonesian children.