More than 25 nations on five continents are hosting activities to celebrate the Global Day of Photonics 2021. The annual event held every Oct. 21 promotes photonics to the public. Companies, research organizations, and organizations involved in photonics engage with their communities to raise awareness about and promote the role of their organization in the photonics ecosystem and value chain. Symposia, radio campaigns, and expert panels, with organizers that include LIGENTEC, the Lithuanian Laser Association, and ISBAT University, Kampala, Uganda (in association with IEEE Uganda Section) are leading the day’s events. Additionally, companies, universities, schools, associations, organizations, and individuals are invited to join a competition that offers a award for the most popular Day of Photonics activity. Participants are encouraged to organize an activity related to photonics, post information about their activity on LinkedIn, and mention #dayofphotonics2021. The main prize is a virtual badge for the most popular Day of Photonics activity. Supported by EPIC (the European Photonics Industry Consortium), the competition will be held on the official Day of Photonics LinkedIn page where all posts about activities are shared. The post with the most reactions (likes, shares, and comments) wins. More information about the Global Day of Photonics can be found at www.day-of-photonics.org.