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? (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.