Informal learning is a complex area, yet one that increasingly involves educational technologists in practice and research. Informal learning includes many different settings, contexts and goals, and draws upon many fields. Two fields that have yielded considerable research literature are museum/free-choice learning and informal science education. While some have defined informal learning as nonschool learning, the nature of informal learning includes dimensions such as location, timing, structure, control, pacing, regulation and content, and so informal learning is not necessarily tied to space. This means that informal learning can and does occur frequently in museums, after-school clubs, botanical gardens, zoos, science centers, and community centers, but can also be engaged in at home and also be integrated within formal school or college settings. Informal science education, museum learning and workplace learning are designed for varied outcomes and have different frameworks. Reasons for assessing for informal learning include to provide formative feedback to participants and to provide evaluation data to improve the organization´s learning goals. Methods for assessment for informal learning encompass both quantitative and qualitative approaches, including traditional tests and measures, but primarily rely on such methods as surveys, group and individual interviews, observations, artifact and product analysis, and sometimes ethnographic or case studies. Emerging educational technologies, such as social media, Web 2.0 tools, eLearning and online learning, provide fertile ground for continuing developments in informal learning and assessment.