Gastric cancer (GC) is one of the deadliest types of cancer in the world. Lymph node (LN) metastasis is a complex and malignant behavior of GC, involving a sequence of biological processes, including decreased adherence to adjacent cells, extracellular matrix (ECM) degradation and lymphatic channel permeation. LN metastasis is directly associated with the treatment response, local recurrence and long‑term survival of patients with GC. Therefore, the molecular mechanisms of LN metastasis in GC development require further investigation. Recently, a large number of clinical studies have focused on the molecular mechanisms and biological markers of tumor invasion and metastasis. However, few articles have broadly summarized LN metastasis in GC, and the molecular mechanisms of LN metastasis are not yet fully understood. In the present review, the molecular mechanisms of LN metastasis in GC will be discussed, including the following aspects: Cell adhesion and movement, ECM degradation, new vessel formation, and molecular pattern differences between metastatic LNs and the primary tumor. This review may lead to a better understanding of LN metastasis in GC, and the identification of new diagnostic markers.