The parish church of Sant'Antonio is Osiglia's main building, a baroque reconstruction of an older medieval church that stood on the same spot. The interior is plain by the standards of Ligurian churches — most of the more elaborate decoration was lost when the church was rebuilt — but the bell tower remains an unmissable landmark in the centre of the village.
A few minutes' walk uphill from the church are the scattered stones of the Del Carretto castle, mostly overgrown but still identifiable. The two together are the village's only built historic interest.