This study was performed to investigate the effects of lignocellulose supplementation (LS) on performance parameters, egg quality, aerobic bacterial load of eggshell, serum biochemical parameters, and jejunal histomorphological traits of laying hens between 18 and 38 wk of age. A total of 640 pullets at 16 wk of age were allotted to 4 treatment groups as 0 kg (control, CONT), 0.5 kg, 1 kg, and 2 kg LS per ton of feed. Body weight (BW), daily feed intake, egg production (EP), egg weight (EW), and efficiency of feed utilization (EF) were determined as the mean of each 3-wk period between 18 and 38 wk of age. Laying hens in the 1 kg LS group had a higher BW mean (1632.1 g, P < 0.001). The highest mean value of EP and EW were observed in 1 kg LS group (81.8% and 57.3 g, respectively), whereas the lowest values were found in the 2 kg LS group (78.6% and 54.4 g, respectively, P < 0.001). The mean of EF was the lowest in the 1 kg LS group (2.72, P < 0.001). There was a decline in eggshell breaking strength and eggshell thickness in the 2 kg LS, when compared with the 0.5 and 1 kg LS groups (P < 0.001). The total aerobic bacterial load of the eggshell was the lowest in the 1 kg LS group (4.7 log10 cfu/mL). The level of aspartate amino transferase and alanine amino transferase showed an incre-ment in both the CONT and 2 kg LS groups (P < 0.001). The high level of LS (2 kg per ton of feed) caused a decline in the levels of IgY, IgA and IgM, when compared to the 0.5 and 1 kg LS groups (P < 0.001). Laying hens in 0.5 and 1 kg LS groups had longer villus height (1335.9 mm) in the jejunum than the others (P < 0.001). These find-ings showed that the 1 kg LS per ton of feed improved EP and EW, eggshell quality, immunoglobulin levels and intestinal morphology, and decreased the total aerobic bacterial load.