The effect of feeding concentrate mix, khat leftover or their mixtures on intake,  digestibility and body weight change were studied using twenty five yearling intact male Hararghe Highland goats with mean initial body weight of 17.8 ± 1.30 kg (mean ± SD). Goats were grouped into five blocks of five animals and randomly assigned to five dietary treatments. Dietary treatments were prepared in such a way that crude protein from concentrate mix (CMCP) was substituted with crude protein from khat leftover (KCP) at a ratio of 0, 33, 67 and 100% on dry matter (DM) basis. Treatments consisted of ad labitum feeding of natural grass hay alone (T1, control) and natural grass hay supplemented with CMCP-100% (T2), KCP-33% + CMCP-67% (T3), KCP- 67% + CMCP-33% (T4), KCP-100% (T5) on DM basis.The study consisted of 90 days growth and 7 days digestibility trials. Supplemented (T2-T5) goats consumed more (P<0.001) total dry matter intake and metabolisable energy than the control (T1). The highest (P<0.001) total crude protein (CP) intake was observed in goats supplemented with T2 (80.5±1.26) which followed by T3 (75.7±1.26), T4 (57.7±1.26), T5 (43.8±1.26) and lowest in T1 (28.7±1.26). Digestibility of dry matter (64-65%) and organic matter (66-67%) were higher (P<0.001) for goats supplemented with T2, T3, T4 and T5 than the goats in T1 (52 and 54% for DM and OM, respectively), but similar (P<0.001) among the T2, T3, T4 and T5 supplemented goats. The effect of dietary treatment on crude protein (CP) digestibility was higher (p<0.001) in order of T1<T4=T5<T3=T2. Average daily gain [-5.6, 61.3, 55.7, 42.2 and 28.4 g/day (SEM=5.9) for T1, T2, T3, T4 and T5, respectively were greater (P<0.001) for T2, T3, T4 and T5 as compared to T1. Goats supplemented with T3 had higher (p<0.001) TDM and TCP intakes and CP digestibility, daily body weight gain compared to goats in T4 and T5.Therefore, it is recommended that supplementation with T3 is optimum combination that could be used to enhance production of goats under small-scale farming system. Further, since supplementation with higher level of khat leftover (T4 and T5)  resulted in higher total DM and CP intakes and digestibility and growth performance compared to control goats, these treatments could also be considered as an alternative feeding strategies under smallholder farming systems.