This study uses panel data from 1,142 Kenya smallholder households over four survey periods to examine the determinants of participation in land rental markets and to quantify the impact of renting land on households’ crop income and total income. We find that land rental markets in Kenya enhance productivity and are equitable. The results are consistent across different estimation methods and model specifications. Dynamic panel models were used to assess the impact of rental participation on households’ crop income and total income. After controlling for the endogeneity of rental market participation and the persistent effects of lagged income, we find that the decision to rent land increased tenant households’ net crop (net total) income by 25.1 (6.6) percent. These percentage gains are inversely related to household landholding size. Hence, land rental markets in Kenya appear to play an important role in raising incomes and reducing poverty for land-constrained smallholder farmers.