The topic collection “Membranes and Membrane Technologies” consists of papers published by Trans Tech Publications Inc. from 2012 up to 2017 and it covers a wide range of engineering solutions in the field of properties research, development, and production of various types of membranes and their use in the technologies for the treatment of the drink water and wastewater, gas separation, bioindustry, etc. We hope this collection will be useful and interesting to a broad audience of researchers and engineers.