Leaf silicon (Si) accumulation may enhance plant performance by mitigating diverse biotic and abiotic stresses. Plants differ widely in leaf Si concentration, but little is known about its variation among tree communities along elevation in tropics. We hypothesized that community-level leaf litter Si concentration should decrease with increasing elevation in tropical moist forests, given species turnover and lower soil Si availability at higher elevation. We examined the elevational pattern of Si concentration in live leaves of trees and leaf litter collected in traps and water extractable soil Si concentration at plots from western Panama and Mount Kinabalu, Malaysia with similar elevational ranges (ca. 600–3200 m elevation). Leaf litter Si concentration decreased with increasing elevation at Kinabalu, but a similar pattern was only found for high elevation (1700–3200 m) plots in western Panama. Leaf litter Si concentration was highly correlated with community-level live-leaf Si concentration across plots. Leaf litter Si was not clearly related with water extractable Si concentration from top 10-cm soil but from 20-50 cm deep soil. Our results suggest that elevation per se has limited explanatory value in determining leaf Si concentrations compared with species composition, parent material and substrate age at a large biogeographic scale.