This study presents the results of a survey conducted in the year 2013 in a subalpine grassland located in Epirus, in northwestern Greece, and concerns the determination of the chemical composition of nine wild plants species (Alopecurus gerardii V., Stipa pennata L., Phleum alpinum L., Trifolium repens L., Lathyrus aphaca L., Lotus corniculatus L., Ranunculus repens L., Achillea millefolium L., and Geranium lucidum L.) at various stages of growth. The highest mean neutral detergent fiber content was determined in S. pennata L. samples with 546 g kg−1 dry matter (DM). The highest mean acid detergent fiber content was determined in samples of A. gerardii L. with 358 g kg−1 DM. For calcium (Ca), the highest average content was determined in the samples of L. corniculatus L. with 9.6 g kg−1 DM. For phosphorus (P), iron (Fe), and copper (Cu), the highest average contents were determined in the samples of R. repens L. with 2.8 g kg−1 DM, 60.2 mg kg−1, and 5.6 mg kg−1 DM, respectively. For magnesium (Mg), the higher average content was found in L. aphaca L. samples with 1.6 g kg−1, for potassium (K) in G. lucidum L. samples with 15.6 g kg−1, for sodium (Na) in A. millefolium L. samples with 15.3 g kg−1, and for manganese (Mn) in P. alpinum L. samples with 37.9 mg kg−1. The chemical composition of plant species meets the nutritional requirements of grazing animals in the investigated area. Among the plant species, legumes and other forbs have the highest nutritional value.