Exposure to toxicants and stresses can cause multiple aspects of transgenerational toxicity in C. elegans. We first introduced transgenerational molecular alterations after exposure to toxicants or stresses, which is reflected by transgenerational genome instability, transgenerational gene expression plasticity, transgenerational alteration in epigenetic-related signals and germline ligand genes, and transgenerational alteration in protective molecular responses. After that, transgenerational developmental toxicity, transgenerational intestinal toxicity, transgenerational neurotoxicity, and transgenerational reproductive toxicity of toxicants were introduced. Moreover, we introduced transgenerational metabolic alterations and transgenerational physiological alterations after exposure to toxicants. Finally, transgenerational lifespan reduction after exposure to toxicants was further discussed.