The order Olenellida Resser and the families Olenellidae, Holmiidae, and Daguinaspididae are recognized. Holmia kjerulfi, H. mobergi n.sp., H. sulcata n.sp., Schmidtiellus mickwitzi mickwitzi, S. mickwitzi torelli, S. reetae n.sp., Wanneria? lundgreni, and 'Fallotaspis' ljungneri are revised or described as new species