While some summer schools have not been officially announced yet, many are very close to their deadlines already. Repeating what I did for Summer 2016 and Winter 2016 / 2017, I will keep this post as an updated list of schools and workshops for the upcoming break. Suggestions are always welcome. I am also interested in recurrent schools with past deadlines since they may be relevant for those reading this post in the future.
Workshop-School on Agents, Environments, and Applications (WESAAC) 2017
May 4-6 (deadline was February 9)
Sao Paulo, Brazil
International School on Mathematics “Guido Stampacchia”: Graph Theory, Algorithms and Applications 4th Edition
May 5-13 (deadline: February 28)
Erice, Italy
Optimization Days 2017
May 8-10 (early registration deadline: April 3)
Montréal, Canada
* Included on March 17 by suggestion of Leandro C. Coelho
1st Canadian Healthcare Optimization Workshop
May 10-11 (early registration deadline: April 3)
Montréal, Canada
* Included on February 21 by suggestion of L.-M. Rousseau
Recent Advances in Algorithms International Computer Science Student School
May 22-26 (deadline was February 10)
St. Petersburg, Russia
Athens Summer School: Techniques in Random Discrete Structures
May 22-27 (deadline not posted)
Athens, Greece
* Included on March 17
BGSMath Monthly Program Random Discrete Structures and Beyond
May 22 – June 16 (early registration deadline: May 15)
Barcelona, Spain
* Included on March 17
Eötvös Loránd University Summer School in Mathematics: Higher mathematics through problem solving
June 6-10 (deadline: May 31)
Budapest, Hungary
ATOM 2017: Multiobjective Optimization Summer School
June 12-16 (early registration deadline: April 30)
Villeneuve d’Ascq, France
* Included on February 20 by suggestion of Sarah Fores
Summer Institute in Computational Social Science
June 18 – July 1 (deadline: February 24)
Princeton, United States
The Machine Learning Summer School
June 19-30 (deadline was February 10)
Tübingen, Germany
Integer Programming and Combinatorial Optimization (IPCO) 2017 Summer School
June 24-25 (deadline not posted)
Waterloo, Canada
The First Israeli Modelling Week
July 2-6 (deadline not posted)
Nahariya, Israel
* Included on March 17
Summer School on Optimization, Big Data and Applications (OBA)
July 2-8 (deadline: March 15)
Veroli, Italy
* Included on February 20 by suggestion of Sarah Fores
ACM Special Interest Group on Genetic and Evolutionary Computation (SIGEVO) Summer School
July 14, 20-21 (deadline not posted)
Berlin, Germany
Swedish Summer School in Computer Science 2017: Boolean Circuit Complexity; Algorithms and Lower Bounds
July 16-22 (deadline not posted)
Stockholm, Sweden
International Summer School on Deep Learning
July 17-21 (deadline: February 24)
Bilbao, Spain
Healthcare Operations Research Summer School
July 21-25 (deadline: March 31)
Enschede, The Netherlands
* Included on February 20 by suggestion of Sarah Fores
7th PhD Summer School in Discrete Mathematics
July 23-29 (deadline: April 30)
Rogla, Slovenia
Argonne Training Program on Extreme-Scale Computing
July 30 – August 11 (deadline: March 10)
St. Charles, IL, United States
Eight Montreal Industrial Problem Solving Workshop
August 7-10 (deadline not posted)
Montreal, Canada
The Jyväskylä Summer Schools (several courses, including Data-driven optimization via search heuristics and Online Social Media Analytics)
August 7-18 (deadline: April 30)
Jyväskylä, Finland
* Included on February 20 by suggestion of Sarah Fores
Graph Limits, Groups and Stochastic Processes Summer School
August 28 – September 2 (deadline: March 18)
Budapest, Hungary
Autumn School: Optimization in Machine Learning and Data Science
August 28-31 (deadline not posted)
Trier, Germany
* Included on February 20 by suggestion of Sarah Fores
ALGO 2017 Parameterized Complexity Summer School
September (dates not posted yet)
Vienna, Austria
130th European Study Group with Industry
September 4-8 (deadline not posted)
Coventry, United Kingdom
Association for Constraint Programming (ACP) Summer School: Hybridization of Constraint Programming and Operational Research
September 18-22 (deadline not posted)
Porquerolles, France
* Included on February 21 by suggestion of L.-M. Rousseau
Thiago Serra 
Hi Thiago. I also have seen the following:
*SUMMER SCHOOL ATOM 2017 on Application and Theory in MultiObjective Optimization, 12-16 June 2017, Lille / Villeneuve d’Ascq, France — Current app deadline for early reg: 30th April 2017
https://ssatom17.sciencesconf.org/
*Summer School on Optimization, Big data and Applications (OBA) – 2017. 2-8 July, 2017, Veroli (Italy).
http://webgol.dinfo.unifi.it/oba/info
*Healthcare Operations Research Summer School in Twente. July 21 – 25, 2017. University of Twente, Enschede, the Netherlands. You must apply before March 31st.
https://www.utwente.nl/en/choir/SummerSchool/
*https://www.jyu.fi/science/muut_yksikot/summerschool/en
The 27th Jyväskylä Summer School 7th – 18th August, 2017 Finland. Deadline 30th of April, 2017.
*http://w2alop.kundenserver.uni-trier.de/events/
Autumn School: Optimization in Machine Learning and Data Science
August 28 – August 31 Trier, Germany
Sarah Fores, Manager of EURO
Hi Thiago,
There’s now a website and registration deadline for the last item: Association for Constraint Programming (ACP) Summer School: Hybridization of Constraint Programming and Operational Research.
http://school.a4cp.org/summer2017/
Deadline (Early) 31st July 2017
Sarah