Currently there is a lack of choice when selecting synthetic materials with the cell-instructive properties demanded by modern biomaterials. The purpose of this study was to investigate the attachment of cells onto hydrogels prepared from poly(2-oxazoline)s selectively functionalized with cell adhesion motifs. A water-soluble macromer based on the microwave-assisted cationic ring-opening polymerization of 2-methyl-2-oxazoline and 2-(dec-9-enyl)-2-oxazoline was functionalized with the peptide CRGDSG or controls using thiol-ene photochemistry followed by facile cross-linking in the presence of a dithiol cross-linker. The growth of human fibroblasts on the hydrogel surfaces was dictated by the structure and amount of incorporated peptide. Controls without any peptide showed resistance to cellular attachment. The benignity of the cross-linking conditions was demonstrated by the incorporation of fibroblasts within the hydrogels to produce three-dimensional cell-polymer constructs.