A side-channel compressor (1) for a fuel cell system (37) for conveying and/or compressing a gas, in particular hydrogen, having a housing (3), having a compressor chamber (30) which is situated in the housing (3) and which has two encircling side channels (19, 21), having a compressor impeller (2) which is situated in the housing (3) and which is arranged so as to be rotatable about an axis of rotation (4), wherein the compressor impeller (2) has conveying cells (28) arranged at the circumference thereof and in the region of the compressor chamber (30), and having in each case one gas inlet opening (14) formed on the housing (3) and one gas outlet opening (16), which openings are fluidically connected to one another via the compressor chamber (30), in particular the two side channels (19, 21), and wherein, in the region of the compressor chamber (30), an encapsulation of the respective side channel (19, 21) is realized by at least one separation region (35) by means of a surface pairing of the compressor wheel (2) and of the housing (3). According to the invention, here, the at least one separation region (35) is formed by a surface pairing of the components compressor impeller (2) and housing (3) such that the respective one component has encircling edges (5), in particular with encircling tips (11), and the respective other component has an encircling, at least approximately planar counterpart surface (23).