In addition to "Danske Studier", Olrik together with Henning Frederik Feilberg and H. O. Lange founded the Danish folklore archive ("Dansk Folkemindesamling"), and served as its first president. He was also the first president of Danmarks Folkeminder, an association founded in 1908, and set up its committees for the study of folklore material and of placenames, both of which are now research institutes at the University of Copenhagen. In addition, with Kaarle Krohn and C. W. von Sydow, he co-founded the international organisation of Folklore Fellows in 1907, and the first issue of "Folklore Fellows' Communications", of which he was co-editor from its inception in 1910, consists of an account by him of the Danish folklore archive. Upon his death, his professorship and with it folklore studies at the University of Copenhagen came to an end; the field was only revived in 1961.