A fundamental question in the design of learning environments is determining the nature of instructional control which will facilitate optimal learning outcomes. The assumptions that increased control in the hands of learners will produce enhanced learning outcomes is untenable. This short paper reviews a select body of research with varying types and levels of control in learning environments and presents a summary of operational definitions of control applied in those studies. Analysis of these definitions revealed variations in the amount of control allowed which is most meaningful if represented on a continuum ranging from maximum program control on the one hand, to maximum learner control on the other. The impacts of control in learning environments is briefly discussed.