The process for preparing nonionic surfactants wherein a narrower molecular weight distribution is obtained by the use of a calcium and/or strontium catalyst which comprises reacting a reactive hydrogen compound selected from the group consisting of monohydric alcohols having from about 8 to about 20 carbon atoms and a difunctional polypropylene oxide polymer having an average molecular weight in the range of 1000 to 5000 with an alkylene oxide having 2 to 4 carbon atoms at a temperature at which the reaction proceeds in the presence of at least a catalytic amount of a basic salt of calcium and/or strontium selected from the group consisting of hydroxide, alkoxide and phenoxides and a catalytic amount of an oxyalkylation catalyst promoter.