| Date | Name | Location |
| May 12-16 | European Conference on Biomedical Optics | Germany |
| May 12-16 | Conference on Lasers and Electro-Optics and XIIIth International Quantum Electronics Conference (CLEO®/Europe-IQEC) 2013 | Germany |
| May 13-15 | 2nd EOS Conference on Optofluidics (EOSOF 2013) | Germany |
| May 13-15 | 3rd EOS Conference on Manufacturing of Optical Components (EOSMOC 2013) | Germany |
| May 13-16 | LASER World of PHOTONICS 2013 | Germany |
| May 13-16 | SPIE Optical Metrology 2013 | Germany |
| May 19-24 | Display Week 2013 | Canada |
| May 29-31 | 9th SEE Congress & Exhibition on Energy Efficiency & Renewable Energy (EE & RE) | Bulgaria |
| May 29-31 | SEE Solar – South-East European Solar PV & Thermal Exhibition | Bulgaria |
| May 29-31 | SMART BUILDINGS South-East Europe | Bulgaria |
| May 29-31 | Save the PLANET: 4th Conference and Exhibition on Waste Management, Recycling, Environment for South-East Europe | Bulgaria |
