Semapa - Sociedade de Investimento e Gestão () is a Portuguese conglomerate holding company with interests in the cement, pulp and paper and environmental services sectors.
The company owns 76.7% of The Navigator Company, previously known as Portucel Soporcel, Europe's largest producer of bleached eucalyptus kraft pulp. It also holds 51% of Secil Group, a manufacturer of cement and its derivatives; and 100% of ETSA, a waste management firm involved in the collection, storage and treatment of animal by-products.
The company is listed on Euronext Lisbon stock exchange and is a constituent of the PSI 20 index.