Sekolah Menengah Sains Hulu Selangor (; SEMASHUR) is a Malaysian boarding school located in Hulu Selangor, Selangor. The 60-acre school is located near Ulu Yam, 30 kilometres north of Kuala Lumpur.
Received Cluster Schools award in 2009 with niche area of rugby, hockey, uniformed bodies and mathematics, SEMASHUR has a good track record when it managed to get number 1 in PMR achievements among SBP schools in 2008 and recorded a hattrick in 2010, 2011 and 2012.
SEMASHUR encompasses an expansive area spanning 60 acres, featuring 40 acres of lush greenery alongside a 7-acre former mining pool. Accessible via the River Tua to Batu Caves (25 km) or the Tg. Pilot - KL road to Rawang (30 km), the institution was officially inaugurated on 16 June 2000 as the 38th Sekolah Berasrama Penuh. Operational duties commenced promptly on 20 June 2000, with the establishment team consisting of the Senior Assistant, Senior Assistant Student Affairs (HEM), and 23 faculty members entrusted with educating the pioneer cohort of 150 students. Subsequently, on 21 July 2000, SEMASHUR welcomed its inaugural batch of 180 Form 1 students, marking the commencement of its academic journey. The school's milestones continued as it admitted its first Form 4 intake in February 2001. A significant accolade was achieved on 9 April 2009, when SEMASHUR was honored with the Cluster Schools award, recognizing its exemplary performance in specialized areas such as rugby, uniformed bodies, and mathematics.
The school basketball team is Blazes Semashur.