The present invention provides a process for producing a fluoroolefin by reacting, in a gas phase, a fluorinating agent and a chlorine-containing alkene or a chlorine-containing alkane in the presence of at least one catalyst selected from the group consisting of chromium oxide, at least part of which is crystallized, and fluorinated chromium oxide obtained by fluorinating the chromium oxide. According to the present process, a target fluoroolefin can be obtained at a high conversion rate of the starting material and with high selectivity.