Background: Previous research has identified higher pedestrian injury rates in London among ‘Black’ children and lower rates among ‘Asian’ children, compared to ‘White’ children. Whilst area affluence protects ‘White’ and ‘Asian’ from pedestrian injury, this is not true for ‘Black’ children. The mechanisms linking ethnicity, disadvantage and child pedestrian injury risk remain poorly understood. Aims: To investigate a series of hypotheses about how ethnicity is related to pedestrian injury risk in London Methods: Five studies analysed quantitative data sources to: (i) identify any ethnic differences in the quality of the road environment where children live; (ii) estimate the quantity of travel-time that children spend exposed to road traffic; (iii) examine whether night-time exposure is more hazardous for minority ethnic children; (iv) explore the relationship between ethnicity, deprivation and injury risk controlling for the quantity and quality of pedestrian exposure; and (v) examine whether ‘group density’ effects can shed light on the relationship between ethnicity, deprivation and injury risk. Results: There was little evidence of differences in the quality of the road environment where ‘White’, ‘Black’ and ‘Asian’ children live. There was no evidence of a difference in the quantity of travel-time pedestrian exposure between ‘White’ and ‘Black’ children and some evidence that ‘Asian’ children walk less than their counterparts. There was no evidence that night-time exposure is more hazardous for minority ethnic children. Controlling for the quantity and quality of exposure changed the relationship between ethnicity, deprivation, and injury risk such that rates among ‘Black’ children were highest in the most affluent areas. ‘Group density’ effects may explain these findings. Conclusions: The quantity and quality of exposure are important mediators of child pedestrian injury risk, although there was little evidence that they explain ethnic inequalities. The findings from this thesis suggest that that the meaning of pedestrian exposure plays a crucial role in complex pathways linking ethnicity to injury risk. Further investigation of individual causal explanations may have diminishing returns, given the evidence from this study that ethnic differences result from inter-related mechanisms.