Casa Lleó i Morera is a modernist building located in the Eixample district of Barcelona, Catalonia, Spain. It was designed by Lluís Domènech i Montaner, one of the most prominent architects of the Catalan Modernisme movement, and was built between 1902 and 1906.

The building is characterized by its rich and intricate decoration, including sculptures, mosaics, stained glass windows, and ironwork. It is a prime example of the Catalan Modernisme style, which was inspired by the Art Nouveau movement that was popular in Europe at the time.

Casa Lleó i Morera was originally built as a residence for the Lleó i Morera family, but it is now home to the offices of the insurance company, Grupo Segur. It has been recognized as a National Monument of Spain and is part of the "Block of Discord," a group of four neighboring buildings in the Eixample district that showcase the work of different Modernista architects.

Visitors can take guided tours of the building and learn about its history and architecture. The interior features a beautiful central staircase and several rooms with original furnishings and decorations. The building also houses a collection of Catalan art and artifacts.