With the depletion in arable land due to climate change, the use of naturally salt-tolerant species to provide forage resources in arid and saline environments has become an emerging strategy. This study surveyed and determined the nutritive value of selected Tunisian vegetative species for use in Mediterranean saline environments. Eighteen wild species were analyzed for their nutrient contents and antinutritional factors. Chenopodiaceae accumulated more NaCl than Poaceae. Arthrocnemum indicum had the highest crude protein (CP) content, and Stipa roterta had the lowest. Poaceae had the highest fiber constituents (neutral and acid) and the lowest oxalate contents. Daily net gas production (GP) in the Chenopodiaceae and Poaceae ranged from 9.5 to 14.5 and from 13.8 to 37.9 ml per 0.2 mg dry matter (DM), respectively. Total phenol content and organic matter digestibility were species dependent. The metabolizable energy (ME) in the tested species ranged from 4.6 to 9.4 MJ kg−1 DM, with Catapodium rigidum and Arthrocnemum indicum having the lowest and highest ME values, respectively. In crux, Chenopodiaceae had the highest NaCl, CP, ME, and oxalate contents but had the lowest fiber and net GP. Sodium chloride content was positively correlated with CP and oxalate and negatively correlated with net GP. In arid and saline environments, where high salinity prevails and fodder resources are scarce, salt-tolerant plants such as Suaeda fruticosa, Arthrocnemum indicum, and Halocnemum strobilaceum could be included in ruminant feeding calendars.