The authors systematically reviewed peer-reviewed studies done with LENA (Language ENvironment Analysis) technology, guided by three research questions: (a) What types of studies have been conducted, and with which populations, since the launch of LENA technology?; (b) What challenges related to use of LENA technology were identified?; and (c) What are the implications for practice and future research using LENA technology? Electronic databases, the LENA Research Foundation website, and bibliographies of already-included studies were searched; 38 studies were identified. The authors selected studies on the basis of purpose, design, participant characteristics, application of LENA technology, and results. They found that LENA technology was used with a range of populations to yield a variety of information. Though challenges and limitations are associated with LENA technology, great potential exists for further research and a resultant increase in evidence-based understanding of early language development and interventions on its behalf.