ICALP 2020 (http://econcs.pku.edu.cn/icalp2020/) and LICS 2020 (https://lics.siglog.org/lics20/) will take place in co-location from 8th till 12th of July 2020 in Beijing, China. The conferences will be preceded by two days of joint workshops, held on July 6th and 7th. We invite proposals of workshops affiliated with ICALP-LICS 2020 on all topics covered by ICALP and LICS, as well as other areas of theoretical computer science. Proposals should be submitted no later than *** November 30th, 2019 *** by sending an email to frederic.blanqui@inria.fr. Due to limited space of the venue we might not be able to accommodate all the proposed workshops. You should expect notification on the acceptance of your proposal by mid December 2019. A workshop proposal submission should consist of: - workshop's name and URL (if already available) - workshop's organizers together with their email addresses and web pages; - short description of the area covered by the workshop and the motivation behind it; - expected number of participants (if available, please include the data of previous years); - planned format of the event; - date preference (July 6th or 7th). As for the format, a standard option is a one-day workshop consisting of invited talks by leading experts and of shorter contributed talks, either directly invited by the organizers or selected among submissions. Deviations from this standard are also warmly welcome, including a shorter or a longer time span than a full day, or other elements of the schedule like open problem sessions, discussion panels, or working sessions. If you plan to have invited speakers, please specify their expected number and, if possible, tentative names. If you plan a call for papers or for contributed talks followed by a selection procedure, the submission date should be scheduled after ICALP 2020 and LICS 2020 notification, while the notification should take place considerably before the early registration deadline. In your submission please include details, in particular the time schedule, of the planned procedure of selecting papers and/or contributed talks. If you plan to have published proceedings of your workshop, please provide the name of the publisher. Please be advised that ICALP-LICS 2020 is not able to provide any financial support for publishing workshop proceedings. We expect the workshops to be financially independent. The expenses related to the participation of invited speakers, production of workshop materials, etc. should be covered from independent sources. On top of standard ICALP/LICS registration fee there will be a moderate registration fee for the workshops that will cover coffee breaks. This workshop fee will be waived for maximum two invited speakers for each workshop. Workshop selection committee: Frédéric Blanqui Naoki Kobayashi Yuqin Kong Michał Pilipczuk Zhilin Wu Lijun Zhang