<p>Heterospecific pollen transfer is ubiquitous in co-flowering communities (i.e., multiple plant species produce flowers and bloom simultaneously) with strong implications for pollination success. Heterospecific pollen transfer may be especially relevant in invaded plant communities where alien pollen affects the pollination success of native plants. However, the mechanisms mediating heterospecific pollen transfer in invaded communities remain poorly understood even though they could help better understand the outcome of plant invasions. In this study, we use structural equation modeling to explore the role of floral trait similarity and pollinator sharing in heterospecific pollen transfer and on the pollination success of native plants in highly invaded coastal communities. Floral trait similarity reduces pollinator sharing between native and alien plants but does not explain the degree of pollinator sharing between native plants. However, increases in pollinator sharing between native plants negatively affected native plants’ pollination success. Unexpectedly, our results showed that increased pollinator sharing between native and alien plants increases pollination success of native plants, suggesting facilitative interactions. However, our results also suggested that native plants’ pollination success decreased with an increase in alien pollen. Overall, our results highlight the importance of considering floral trait similarity and pollinator sharing in mediating the complex dynamic of heterospecific pollen transfer between native and alien plants and its consequences on native pollination success with implications for plant invasion success.</p>