Post-pollination pre-zygotic barriers involve interactions between the pollen, pistil and ovules that impede fertilization by heterospecific pollen. These barriers act sequentially when pollen from different donors simultaneously pollinates the same flower, by inhibiting the development of foreign pollen or by conferring a fecundation advantage to the specific pollen tube. Here, we investigated the presence and strength of post-pollination barriers in an orchid lineage that lacks pollinator specialization. We then evaluated the relationship between early and late post-pollination pre-zygotic barriers and their chronology of insurgence.