Astronomy

• Cassini–Huygens, mission to Saturn and Titan
  • Huygens (spacecraft), the probe of the Cassini-Huygens mission which landed on Saturn's moon Titan in 2005
• 2801 Huygens, an asteroid
• Huygens (crater), martian crater
• Mons Huygens, a mountain of Earth's Moon
• Huygens Gap, in the rings of Saturn

Physics

• Huygens law; see one of:
  • Huygens law (pendulums)
  • Huygens law
• Huygens–Steiner theorem

Optics

• Huygens–Fresnel principle
• Huygens' principle, see Huygens–Fresnel principle
• Huygens eyepiece, first compound eye piece
• Huygens Software, a microscope image processing package

Mathematics and games

• Huygens lemniscate, a figure eight curve
• König–Huygens formula, see Steiner–Huygens

Other

• Huygens-Fokker Foundation
• Huygens' tritone, a musical interval
• Huygens' engine
• Christiaan Huygens College, High School in Eindhoven, Netherlands.
• Huygens College, High School in Heerhugowaard, Netherlands.
• The Christiaan Huygens, a ship of the Nederland Line.
• Huygens Scholarship Programme for international students and Dutch students
• W.I.S.V. Christiaan Huygens: Dutch study guild for the studies Mathematics and Computer Science at the Delft University of Technology
• Huygens Laboratory: Home of the Physics department at Leiden University
• Huygens Supercomputer: at SARA, Amsterdam
• The Huygens-building in Noordwijk, Netherlands
• The Huygens-building at the Radboud University, Nijmegen, The Netherlands.