Sementina is a former municipality in the district of Bellinzona in the canton of Ticino in Switzerland . It ceased to exist on 2 April 2017 when it and the municipalities of Camorino , Claro, Giubiasco , Gnosca , Gorduno , Gudo , Moleno , Monte Carasso , Pianezzo , Preonzo , and Sant'Antonio were merged into the municipality of Bellinzona.

Sementina has an area, as of 1997, of 8.25 square kilometers (3.19 sq mi). Of this area, 1.61 km2 (0.62 sq mi) or 19.5% is used for agricultural purposes, while 5.56 km2 (2.15 sq mi) or 67.4% is forested. Of the rest of the land, 0.84 km2 (0.32 sq mi) or 10.2% is settled (buildings or roads), 0.21 km2 (0.081 sq mi) or 2.5% is either rivers or lakes and 0.26 km2 (0.10 sq mi) or 3.2% is unproductive land.

Of the built up area, housing and buildings made up 6.3% and transportation infrastructure made up 2.1%.