Wnt signaling has been shown to engage a multifunctional pathway that is involved in the regulation of a wide variety of normal and pathologic processes, including embryogenesis, differentiation and tumorigenesis. Recent studies have demonstrated that Wnt5a expression is frequently seen in various human cancers. In contrast to the transforming members of the Wnt family, shown to be upregulated in many cancers, the role of Wnt5a is still controversial in its expression in different tumors. There is increasing evidence that Wnt5a has tumor suppressor function in some malignancies, and in addition, it elicits promigratory and proinvasive effects via the planar cell polarity pathway, which suggests that Wnt5a might be an effective marker for the progression and prognosis of tumors. Obviously,the outcome of Wnt5a signaling is dependent on a multitude of variables, ranging from receptors, downstream effectors and inhibitors, to extal influences coming from the tumor microenvironment. This review will focus on the role of Wnt5a signaling and, as a consequence, provide an outline describing the expression and functions of Wnt5a in cancer progression.