Post-translationally modified peptides are important regulating molecules for living organisms. Here, we report the stereoselective total synthesis of β-1,2-linked l-arabinosylated Fmoc-protected hydroxyproline building blocks and their incorporation, together with sulfated tyrosine and hydroxyproline, into the plant peptide hormone PSY1. Clean glycopeptides were obtained by performing acetyl removal from the l-arabinose groups prior to deprotection of the neopentyl-protected sulfated tyrosine.