Pattern separation and pattern completion are important functions of the hippocampal formation involving particularly the dentate gyrus (DG)-CA3 mossy fiber system. These functions allow for the differentiation of similar memories as well as a generalization of a memory trace in response to incomplete sensory inputs. The salience of hippocampus-dependent contextual fear memories is controlled by local somatostatin (SST)-positive interneurons that regulate the excitability of DG granule cells. In the current study we investigate if SST-positive interneurons contribute to fear memory specificity via pattern completion/ separation mechanisms. Hence, SST-positive interneurons were chemogenetically inactivated in the dorsal DG during the retrieval of a contextual fear memory. To test for contextual pattern completion/ separation, mice were subjected to one of three retrieval contexts that shared all (original context), some (altered context) or none (novel context) of the features of the training context. Control mice were able to differentiate the novel context from the altered and original one, while the inactivation of SST-positive interneurons in the DG-CA3 system evoked similar freezing levels to all three contexts. Additionally, we detected an overall increase in the excitability of the DG-CA3 axis 24h after fear conditioning pointing to its potential engagement in fear encoding and consolidation which was also evident by cFos immunohistochemistry. Together, the inactivation of SST interneurons during contextual fear memory retrieval may decreases memory recall specificity via disinhibition of the DG-CA3 mossy fiber system. This is of relevance for stress-induced neuropsychopathologies such as posttraumatic stress disorder, where an over-generalization of aversive memories is observed.