Pancreatic cancer (PC) is a malignant tumor with high malignancy and poor prognosis. Chemoresistance and immune escape caused by the hypoxic and immunosuppressive characteristics of its tumor microenvironment (TME) have become important reasons for the low cure rate. In tumor tissues, lymphocytes aggregate to form organized ectopic lymphoid structures, known as tertiary lymphoid structures (TLSs). TLSs exist in both intratumoral and peritumoral tissues of PC. TLSs play a role through anti-tumor immune responses in various tumors including PC, and are associated with favorable prognosis. Inducing the formation of TLSs can promote tumor antigen presentation, maturation and differentiation of T and B cells, enhance the ability to recognize and kill tumor cells, and improve anti-tumor immune responses. TLSs in PC are related to tumor occurrence and development, long-term prognosis, and good treatment responsiveness, providing new strategies and perspectives for PC therapy. This article reviews the formation of TLSs in PC, their anti-tumor effects, and applications in PC prognosis and treatment, providing a reference for in-depth research on TLSs in PC.