In the last 5 years, there have been several literature reviews or meta-analyses investigating various aspects of STEM education; however, they have investigated a specific aspect of STEM, e.g. robotics, or digital games, or Early childhood, or Teacher perspectives. In addition, a broad-reaching review on STEM integration has not been conducted in the past 10 years. This article reports findings from a Systematic Qualitative Literature Review concerning STEM education for children aged 4–12 in formal education contexts. To provide context, the article initially presents descriptive findings (date and country of research, age of participants, research setting, and research methodologies used) in the 60 research articles that are included for analysis. The article then answers three research questions regarding the: (1) level of integration evident in the studies; (2) role of engineering in any such integration; and (3) teaching approaches used in the studies. Findings from this research suggest that there is still much work to be done to move from scenarios where STEM integration is claimed but is not evident in practice. To do so we encourage educators and researchers to (a) focus on authentic interdisciplinary approaches rather than the siloed approaches evident in the existing research; and (b) use a teaching approach such as problem-based or project-based learning that provide opportunities for authentic integration.