Polyhalogenated carbazoles (PHCs), with a complex chemical structure similar to polychlorinated dibenzofurans, are a class of emerging environmental organic contaminants. There are 135 congeners for PHCs with a pure halogenation. Most of PHCs are not man-made products. Although PHCs in the environment were firstly discovered in the 1980s, these emerging halogenated compounds were not seriously considered until recent years. Recently, more than 20 PHCs have been detected in sediment and soil samples. In addition, studies have shown that PHCs exhibited dioxin-like toxicity and were persistent and bioaccumulative. Therefore, it is very important to understand the distribution, origins and ecotoxicology of PHCs for a better assessment of their environmental risks. To date, research on the environmental behaviors of PHCs is relatively limited and warrants further investigations. In this review, the environmental distribution, source, analytical methods and toxicity of PHCs were summarized and future research needs were outlined.