Monolignol transport during lignification is a partially solved puzzle: both the mechanism(s) and the transported form of monolignols are unknown in developing xylem of trees. We tested a hypothesis of an active, plasma membrane (PM)-localized transport of monolignol monomers, dimers, and/or glucosidic forms with membrane vesicles prepared of developing xylem, phloem, and lignin-forming, tissue-cultured cells of Norway spruce (Picea abies L. Karst.), as well as of a control material, non-lignifying tobacco (Nicotiana tabacum L.) BY-2 cells. Xylem and BY-2 vesicles transported both coniferin and p-coumaryl alcohol glucoside, but inhibitor assays suggested this transport being over the tonoplast. Based on similar inhibitor assays, lignin-forming, tissue42 cultured cells of spruce had coniferin transport putatively localizing on PM. Liquid chromatography-mass spectrometry (LC-MS/MS) analysis of membrane proteins isolated from spruce developing xylem, phloem and tissue-cultured cells revealed multiple transporters. These were compared to a transporter gene set that was gained by a correlation analysis with a selected set of spruce monolignol biosynthesis genes. Biochemical membrane vesicle assays showed no support for the ABC-transporter-mediated monolignol transport but point to secondary active transporters (such as MFS- or MATE-transporters). In contrast, proteomic and co-expression analyses suggest a role for ABC-transporters and MFS-transporters.