Ferns are the second most diverse group of higher plants on the planet. However, the metabolic processes of these plants, as well as their reaction to the influence of various environmental factors, benefit from new investigation. In seed plants, an important role of the lipid fatty acid (FA) composition in plant response to a variety of environmental conditions has been repeatedly demonstrated. In this paper, the composition of FAs in the epiphytic ferns, Platycerium bifurcatum and Asplenium nidus, and the terrestrial fern, Asplenium trichomanes was analyzed by gas-liquid chromatography with mass spectrometry. The data obtained clearly indicate that epiphytic ferns have several distinctive features in the composition of their FAs. They are characterized by a high level of saturated FAs (about 50%) and a great variety of very-long-chain FAs (VLCFA). This strongly contrasts with the FAs composition in the terrestrial fern in which unsaturated FAs prevail. High levels of saturated fatty acids, in particular palmitic acid (16:0), together with a high VLCFA content, can be a necessary component in complex interactions with microorganisms. Thus, the specific FA composition of P. bifurcatum and A. nidus may act both as a protective mechanism against the penetration of bacteria and pathogenic fungi, and as a mechanism for the interaction of the epiphytes with saprophytic fungi. It is likely that the composition of FAs in the epiphytic ferns is determined by their habitat and plays an active role in the interaction of plants with their environment.