Andrew White from the quantum technology laboratory at the University of Queensland, Australia, maintains an excellent web page listing conferences related to quantum technology around the world. You can find his most recent listing for 2018 conferences here.
In addition to the conferences shown on the list mentioned above, here are some additional conferences:
The Quantum Technology International Conference (QTech 2018) will be held in Paris, France from September 5-7, 2018. The objectives of the conference is to present the latest developments of quantum technologies in the domains of quantum communication, computation, simulation, sensors and metrology, and their implementation using various platforms from atoms and ions to solid states, superconducting circuits and optics. You can view their web site for program and registration information here.
Also, the 3rd International Conference on Quantum Optics and Quantum Communications will be held on September 10-11, 2018 in London, UK. Click here for details.
The International Conference for Young Quantum Information Scientists (YQIS) will be held at the University of Vienna (Austria) from September 17-21, 2018. This conference offer introductory lectures by leading researchers in theoretical and experimental quantum physics to an audience of local and international master and PhD students as well as postdocs. Additionally, this gathering facilitates stimulating discussions between the students and visiting researchers based on scientific oral and poster presentations by the early stage researchers and the invited speakers. The deadline for registration is June 30, 2018. For more details, click here.
A workshop on Quantum Techniques in Machine Learning (QTML 2018) will be held from November 12-16, 2018 in Durban, South Africa. The conference will bring together experts from Quantum Computing and Machine Learning to discuss the latest progress in the rapidly growing field of Quantum Machine Learning. Click here for details.