Relatively little attention has been paid to pollinator-mediated interactions among invasive and native plants in spite of the fact that pollen transfer between species in invaded communities has been shown to occur. In this study, we investigated the impact of pollen deposition from the invasive plant species Lythrum salicaria on seed set in a native species that is a member of the same family, Decodon verticillatus. Whole plants were subjected to hand pollination by conspecific (D. verticillatus only) or mixed (a 1:1 mixture of D. verticillatus and L. salicaria) pollen to determine if the addition of a mixed pollen load interferes with the ability of D. verticillatus pollen to set seed. We found the mixed pollen treatment reduced D. verticillatus seed set by 33.3% relative to the conspecific pollen treatment. Our study demonstrates that invasive plants have the potential to negatively impact the reproductive success of a native species through pollinator-mediated interactions. We discuss the potential implications of our findings to the evolution and persistence of native plant populations in invaded communities.