In recent years there has been an increase in the number of children going to school in England who do not speak English as a first language. We investigate whether this has an impact on the educational outcomes of native English speakers at the end of primary school. We show that the negative correlation observed in the raw data is mainly an artefact of selection: non-native speakers are more likely to attend school with disadvantaged native speakers. We attempt to identify a causal impact of changes in the percentage of non-native speakers within the year group. In general, our results suggest zero effect and rule out negative effects.