Abstract OBJECTIVE. Limited information is available on how sleep and play positions affect infant gross motor skills and occupational development. The overall objective of this descriptive developmental pilot study was to compare normative and sampled infants relative to sleep and awake positioning using the Denver II Gross Motor Sector. METHOD. A cross-sectional sample of 66 infants 2.0 (n = 23), 4.1 (n = 26), and 6.0 (n = 17) months of age were administered the Denver II Gross Motor Sector. Caregivers identified infants’ primary sleep positions and amount of awake-time in prone. Data were analyzed using chi-square goodness-of-fit tests. RESULTS. The sample of 2.0-month-old supine and side sleeping infants differed significantly from the normative population on three gross motor milestones. Two-month-old infants spending 15 min or fewer of awake-time in prone passed the gross motor milestones at significantly lower percentages than the normative population. No significant differences were noted between sampled and normative populations at 4.1 and 6.0 months of age. CONCLUSION. Results suggest that infant gross motor development may be related to sleep and play positioning. Information regarding infants’ sleep and awake positioning may be important to occupational therapists when evaluating gross motor development. Implications for caregiver education and future research are proposed.