We present the first study of the forest vegetation dominated by Tilia platyphyllos growing on cal- careous rock outcrops in the northern part of the Iberian Peninsula. This vegetation is confined to steep rocky slopes of mainly northern aspect in limestone areas. Based on a dataset of 53 relevés recorded during the summer of 2019 and compared with so far described associations of the order Aceretalia pseudoplatani (118 relevés), we describe the new association Helictotricho...