The Serra de Collserola (Catalan pronunciation: [ˈsɛrə ðə kuʎsəˈɾɔɫə]), or simply Collserola, is a mountain range between the rivers Besòs and Llobregat. It is part of the Catalan Coastal Range.

These mountains separate Barcelona from the Vallès plain and their tallest peak is the Tibidabo, at 512 m. Other main summits are: Turó del Puig, Puig d'Olorda, Turó de Valldaura, Turó de la Magarola, Puig d'Ossa and Puig Madrona. The valleys of the Llobregat and Besós Rivers, the plain of Barcelona, and the Vallès basin, mark the geographical boundaries of the Collserola massif.

To preserve the area, in 1987 the Parc de Collserola (Collserola Park), which has an area of 84.65 km², was established. It is the largest metropolitan park in the world - 8 times larger than the Bois de Boulogne in Paris, and 22 times larger than Central Park in New York.

In the park, over a thousand major plants and around thirty plant communities have been catalogued; including forests of Aleppo pines and nut pines, evergreen oaklands, riverside copses, maquis and scrublands, brush and Savannah grasslands. This diversity allows for the existence of a rich, varied wildlife; including wild boar, genets, stone marten, badger, rabbit, and squirrel; blue tits, whitethroats, treecreepers, woodpeckers, bee eaters, doves, goshawks, sparrow hawks, and rat-catching eagles; salamanders, newts, green tree frogs, the small southern frog, toads, the small spotted toad, the Mediterranean turtle, the giant turtle, the ocellated lizard, snakes and so on.