Water lily aphids, Rhopalosiphum nymphaeae, are a polyphagous species of insect that feed on a variety of host plants including members of the Lemnaceae family. Many studies have focused on the relationship between herbivore preference and performance on different host plants, and as such the goal of this study was to determine if there is any relationship between host plant preference and performance of the water lily aphid on three different species of duckweed, including one invasive duckweed. Aphid preference was determined through a series of choice tests, which showed that the aphids preferred Spirodela polyrhiza over Landoltia punctata over Lemna minor. Water lily aphids also initially preferred the species they were reared on, even if it was not an overall preferred species, suggesting that familiarity plays a role in shaping host preference. To determine performance I measured offspring growth, reproduction and survival on all three species of duckweed. Aphids had the lowest performance levels on Lemna minor and the highest on Landoltia punctata and Spirodela polyrhiza. Aphids preferred and performed the best on the least nitrogen rich duckweed.