The phylogenetic interrelationships in Primulaceae, Myrsinaceae, and Theophrastaceae were investigated using DNA sequence data from the chloroplast genes atpB, ndhF, and rbcL. The three genes were analyzed separately, together, and in combination with morphology, using parsimony jackknifing. The sequence data are further explored by analyses of first and second codon position only, third positions only, and transversions only. The results show that all codon positions contribute group support to the ndhF tree, whereas third codon positions provide most of the structure in the atpB and rbcL trees. Analyzed separately, transversions in atpB and rbcL have little structure, whereas in ndhF they produce a well-resolved tree. We conclude that the most informative and robust results are obtained from analyses with all codon positions included and that the tree resulting from the combined analysis of all available data provides the best estimate of phylogeny.The results show that Maesa is sister to all other taxa from the three families. Theophrastaceae are well supported, but both Myrsinaceae and Primulaceae are paraphyletic. We conclude that four families should be recognized, Maesaceae, Theophrastaceae, Primulaceae, and Myrsinaceae. For all families to be monophyletic, Samolus was transferred to Theophrastaceae, and Lysimachia, Anagallis, Trientalis, Glaux, Asterolinon, and Pelletiera were moved to the Myrsinaceae together with the genera Coris, Ardisiandra, and Cyclamen.