The goal of this study was to investigate effects of different levels of silicate supplementation in weaning to finishing pigs. A total of 96 piglets [(Landrace × Yorkshire) × Duroc] with initial body weight of 11.30 ± 0.02 kg were used for 16 wk (six replicate pens with four pigs per pen). Dietary treatment consisted of 0% (CON), 0.1% (T1), 0.5% (T2), and 1.0% (T3) silicate in the basal diet. Inclusion of 0.1% dietary silicate increased (P < 0.05) body weight, average daily gain, and gain-to-feed ratio in 0–16 wk. In addition, inclusion of 0.1% dietary silicate increased (P < 0.05) crude protein digestibility in 8 and 16 wk, whereas it decreased (P < 0.05) Escherichia coli count and ammonia emissions throughout the study period. Additionally, inclusion of dietary silicate increased (linear, P < 0.05) white blood cell in 4 wk, whereas it increased (quadratic, P < 0.05) white blood cell counts in 8 and 16 wk. Blood urea nitrogen decreased (quadratic, P < 0.05), and lymphocyte and foot and mouth antibodies increased (quadratic, P < 0.05) when silicate level increased. In conclusion, supplementation of 0.1% silicate in the diet showed positive effects in weaning to finishing pigs.