Background: Enjoyment and play during school lunchtime are correlated with children's physical activity. Despite this, there is an absence of studies reporting children's enjoyment of play during school lunchtime breaks. The purpose of this study was to examine the intraday and interday reliability of children's enjoyment of school lunchtime play. Methods: Surveys used to assess children's enjoyment of lunchtime play were distributed to and completed by 197 children (112 males, 85 females), aged 8-12 years attending an elementary school in Victoria, Australia. Children completed the surveys during class before lunch (expected enjoyment) and after lunch (actual enjoyment) for 5 days. The intra- and interday enjoyment of school lunchtime play reliability were determined using a weighted kappa. Results: Intraday kappa values ranged from fair (0.31) to substantial (0.75) within each of the 5 days (median kappa = 0.41). In comparison, "expected" (0.09-0.40; median 0.30) and "actual" (0.05-0.46; median 0.28) interday enjoyment of lunchtime play displayed low reliability. Conclusions: Children's enjoyment of lunchtime play appears to be more consistent within days than across days. The findings suggest that assessment of children's enjoyment of lunchtime play once on a single day would be representative of a particular day but not necessarily that particular school week.