The current work is an investigation of the acute toxicity and periodic pathological status in fourth instar larvae anal gills of Asian tiger mosquito, Aedes albopictus exposed to various sodium hypochlorite (NaOCl) levels over a 24-h test period. The static renewal test method of acute lethal concentrations determination was used, and water temperature was maintained at 24.0 ± 0.5 ºC. NaOCl data obtained during acute toxicity tests were determined using the probit analysis method. The median lethal concentrations (8-h, 12-h, and 24-h LC₅₀) of NaOCl for A. albopictus larvae were estimated as 6046.848, 3075.075, 671.423 mg/L, respectively. A. albopictus larvae were exposed to 100, 200, and 400 mg/L of NaOCl for lethal toxic tests. Anal gills of exposed A. albopictus larvae frequently exhibited shrinkage of epithelium, rupture of tracheoles, and poor-organized cuticle and pathological changes became more pronounced with increasing concentrations.