Thirty years after the return of grey wolves (Canis lupus) to the French Alps, the number of livestock losses is on the rise despite livestock guarding dogs (LGDs) being widely used. Their relevance is, therefore, questioned by some sheep owner associations. To date, no study has investigated how LGDs interact with wolves in pastures. We present the results of a 6-year study totalling 3,300 hours of direct night-time observations to record the nature, frequency and outcomes of LGD-wolf interactions in the southern French Alps. We recorded 476 wolf events in the presence of LGDs, including 175 interactions, 66% of which were agonistic. Most (65%) of the interactions occurred at a distance > 100 m from the flock and on average involved more LGDs than wolves. In the presence of LGDs, wolves approached the flocks 134 times resulting in no attack (65%), attacks with no sheep victim (24.6%), or attacks with ≥ 1 sheep victim (10.4%). Our results suggest that LGD-wolf interactions are complex and do not simply occur in the immediate vicinity of the flock. We recommend using groups > 6 LGDs and reinforcing the presence of LGDs in a wider radius around the flock to limit the presence of isolated groups of sheep and to improve protection against wolf attacks.