Recently, the construction industry has shown great interest in the use of a variety of industrial by-products and waste, as well as used consumer products. The Special Issue "Recycled Materials for Concrete and Other Composites" presents the results of the latest research on the synthesis of composite materials produced using various types of waste materials, in particular, mortars and concretes, and their physicochemical and mechanical properties. The topics of the published articles also cover a number of other aspects, including the efficiency of the production of composite materials containing waste materials, their resistance to corrosion, the interactions of wastes and plasticizers, and the leaching of metal ions from the produced composites. Both interesting and practical solutions and the results of laboratory tests are presented. The published research clearly shows that the use of waste and recycled materials for the production of composite materials is a key element in reducing the consumption of natural resources and the amount of waste generated, which has a positive impact on environmental protection. The topics of published scientific works are relevant for both scientists and engineers from the construction industry.