Calcium is one of the most common and, therefore, cheap metals on earth. It has long been used for the modification and alloying of heavy metal alloys, in particular lead and copper. As a modifier, it is used in cast irons and steels. More recently calcium started to be used in light alloys based on aluminum and magnesium. This review covers the applications of metallic calcium, its effect on the structure and properties of various alloys. Over the past few years, systematic studies of aluminum-calcium-eutectic alloys have been carried out and it has been found that their casting properties are no worse than that of silumins, and they can be subjected to hot and cold rolling with a high degree of deformation. Threefold and more complex phase diagrams of systems including calcium were constructed, and multicomponent alloys based on them were investigated. All this allowed us to distinguish several groups of new promising calcium-containing aluminum alloys: (1) alloys hardened without quenching due to nanosized Al3Zr, Al3Sc and Al3(Zr,Sc) phase particles precipitated during annealing; (2) high-strength alloys doped with traditional hardening elements of aluminum solid solution, zinc and magnesium; (3) composite-type alloys containing more than 20% of eutectic intermetallics in their structure. These alloys have a reduced density, an improved set of performance properties, increased corrosion resistance and high manufacturability when making cast and deformed semi-finished products.