Leaching, the release of elements to water from dead leaves, may play a significant role in ecosystem elemental cycling. However, little is known about silicon (Si) leaching. We investigated patterns of Si leaching by using dead leaves of 12 tree species collected in Lambir Hills National Park, Malaysia. Water-soluble Si concentration per unit leaf mass was determined after 4, 12 and 24 hours of Si extraction to water (1:80 sample-to-water ratio). Leaf Si concentration per unit leaf mass was measured after Si extraction with alkaline digestion (1% NaCO₃) at 85°C. The amount of Si dissolved to water increased with time of extraction. Water-soluble Si differed among species which differed in leaf Si concentration. Water-soluble Si concentration increased with increasing leaf Si concentration, but the fraction (water-soluble Si / leaf Si) decreased from 24% to 1% with increasing leaf Si concentration. Thus, water-soluble Si occupies larger fractions of Si in Si-poor leaves than in Si-rich leaves. Furthermore, water-soluble Si fraction was generally lower compared with other elements such as potassium and phosphorus (Schreeg et al. 2013). In conclusion, we suggest that short-term leaching of Si is relatively small from dead leaves of lowland tropical trees.