This paper proposes a measure of consensus for group decision making in the hesitant fuzzy linguistic term sets framework. An extension of the set of hesitant fuzzy linguistic term sets is considered to capture differences among discordant assessments. The difference between a pair of disjoint assessments is given by a measure that takes into account the gap between them. The proposed measure of consensus is defined using this extension, and, as a result, we obtain more accurate values, i.e., the new measure is able to distinguish among group consensus levels that were indistinguishable according to existing measures of consensus. An illustrative example is provided to show the potential of the proposed consensus degree, the process of its computation and a comparison with an existing approach based on a similarity among decision makers.