The present study was aimed to compare the effect of two mixtures of medicinal plants as feed additives on the lamb's performance. The first additive consisted of a 1:1:1 Rosemary, Thyme, and Peppermint mixture (RTPM). While, the second additive consisted of a 1:1:1 Lemongrass, Parsley, and Coriander mixture (LPCM). Twelve male Saidi lambs of 20.49 ± 0.76 kg body weight (BW) were randomly allocated into three groups. The first group received a control diet (concentrate-to-forage ratio: 70:30) without additives, the second group received a control diet supplemented with 1.5% RTPM on a dry matter (DM) basis, and the third group received control diet supplemented with 1.5% LPCM on a DM basis. The experiment lasted for 150 days. The results showed that RTPM had lowered DMI (P = 0.0692) while the LPCM had higher DMI as compared the to control. The supplementation of RTPM or LPCM did not have a significant effect on nutrients digestibility and their nutritive value. Similarly, ruminal pH, ruminal temperature and total volatile fatty acid (TVFA) were not affected (P > 0.05) by RTPM or LPCM, while ammonia-N (P = 0.0043), and total nitrogen (P < 0.0001) were higher for RTPM and LPCM than Control. The average daily gain (ADG), total weight gains (TWG), and feed conversion ratio (FCR) of the lambs receiving RTPM or LPCM rations were greater (P ≤ 0.0057) than the control diet. The economic efficiency was improved by the RTPM addition (P < 0.0001) while the LPCM diet decreased economic efficiency compared to the control.