Kızsini is a village in Daday District, in Kastamonu Province, Türkiye. Kızsini lies at 1,317 m above sea level, in the Küre mountains. It has 87 inhabitants. The nearest city is Kastamonu, 33 km to the southeast. Among the landmarks around are Mahmut Bey Mosque (21 km) and Germeçtepe Dam (19.1 km).