The 17th International Symposium on the Science and Technology of Lighting (LS:17) aims to provide an excellent forum for scientists and engineers worldwide, in both academia and industry, to share and exchange the latest progress on the Science and Technology of Lighting Systems. LS has a more than 45-year history and since the 1st LS (LS:1) in 1975 in Loughborough, United Kingdom has been held regularly in various continents. Especially for this time, LS17 will be collocated with the 11th International Conference on Energy Efficiency in Domestic Appliances and Lighting (EEDAL). Both conferences will be held at the campus of the University of Toulouse III – Paul Sabatier, France from Monday, November 8th to Wednesday 11th of November 2021. Paper submission for LS:17 is open since January 22nd and the deadline fixed in April 23rd All submitted papers will be peer-reviewed by the International Scientific Committee. Accepted papers will be included in the conference proceedings. The proceedings volume will be published in electronic form by the conference-leading sponsor organization and all papers will be listed by IEEE Xplore® which enables invited and contributed papers to be referenced with an individual DOI number. Join us to these two exciting events and submit your papers! https://eedal-ls21.sciencesconf.org/