AKT is a serine/threonine kinase activated downstream of integrin, which is a receptor for various pro-proliferation and bioactive substances as well as the extracellular matrix receptor. The activation of AKT often contributes to tumorigenesis and plays a role in regulating cell motility, which is critical for local invasion and metastasis. In recent years, it has also drawn attention as a target of new molecular-targeted agents. When analyzing the role of AKT in cancer cells, it is important to consider the microenvironment and variations of cancers. In this review, a basic overview of the role of AKT in normal and malignant tissues is provided, along with an in-depth discussion of its role in gastric cancer and its potential as a target for therapy.