Embodiments of an alignment system for a table saw are disclosed, wherein the table saw has a rotatable blade that extends through its table top, the table top having spaced indicia oriented in a direction parallel to the plane of the blade, comprising an elongated fence having first and second end portions, at least the first end portion having a mechanism for securing the fence on the table saw, an elongated portion attached to the first end portion and extending over the table top, the fence being normally oriented so that the elongated portion is parallel to the plane of the blade and being laterally adjustable relative to the blade, at least two light emitting units mounted on the fence at spaced locations along the length of the fence, each unit configured to direct light on a first side of the fence toward the indicia and enable an observer to determine if the fence is oriented parallel to the indicia.