**2. Scope of this chapter**

The authors aimed to present detailed review and analysis of design, synthesis, microstructures and mechanical properties of Mg containing MPEAs from all the existing scientific articles on the topic available to this date. The presence of multiple principal elements in an alloy makes it difficult to interpret the reasons behind the behavior of HEAs. This study presents the possible interpretations of the structure-properties-processing relationship of Mg containing alloys in both equiatomic and non-equiatomic compositions. **Figure 1** shows the gradual increase in interest in Mg-HEAs.

**Figure 1.** *Year vs number of publications of Mg containing HEAs.*
