Dairy goats provide food and financial security through their milk and meat. The main basal diet for confined dairy goats in Kenya is Napier grass (Pennisetum purpureum Schumach). However, optimal milk production is hampered by the high cost of protein and energy supplements that are required while feeding the grass. The protein supplement affordability is of greater limitation among farmers, therefore use of protein-rich forages in a supplement can lower the concentrate cost. Information on the optimal protein and energy inclusion levels in a forage-based concentrate for dairy goats is hardly available in Kenya. A study was therefore conducted whereby Leucaena (Leucaena leucocephala Lam.) leaf hay was used as the main protein source in four concentrates formulated with crude protein (CP) content (gkg-1) and metabolizable energy (ME) levels (MJkg-1), respectively, of: 135, 12; 160, 10; 185, 8; and 210, 6; respectively. A fifth supplement was formulated, representing the commonly used cattle dairy meal (160 g CPkg-1 DM and 10 MJ MEkg-1 DM, respectively), using commercial sunflower seedcake as a protein source. The concentrates were fed at 300 gday-1 to lactating Toggenburg dairy goats on Napier grass basal diet, in a 5 x 5 Latin square design. The total dry matter intake by the goats was 1.059-1.128 kg DM/goat day-1, with a milk production of 221.3-285.5 mL/goat day-1. It was concluded that the appropriate CP and ME levels in the Leucaena-based concentrate are 135 gkg-1 DM and 12 MJkg-1 DM, respectively. It was recommended that other protein-rich forages be explored