Through a review of the literature, this paper asserts that four distinct styles of laboratory instruction have been utilized throughout the history of chemistry education: expository (traditional), inquiry, discovery, and problem-based. Although these instructional styles share many commonalities and oftentimes their labels are used interchangeably, each style is unique and can be distinguished from the others by a set of three descriptors: outcome, approach, and procedure. This taxonomy of laboratory instruction styles, in which the distinguishing features of each style are highlighted, is presented along with current research findings, to establish a research agenda that measures the effectiveness of each style of instruction against the desired learning outcomes.