The 13th edition of the Winter School will take place at the Hotel Londres (https://www.hotelondres.com/en/) , Estoril, from the 17th to the 22th of January of 2027. In the spirit of the previous editions, the main objective of the school is to provide an opportunity for PhD students to get together and attend high level courses in the field of Network Optimization. In this edition of the school, the lecturers and subjects to be addressed are: Claudia Archetti ( University of Brescia) - Efficient exact and heuristic algorithms for the Inventory Routing Tolga Bektaş (University of Liverpool) -Compact formulations, projections and some polyhedral results for the vehicle routing problem Christina Büsing (Aachen University) - Dealing with uncertainty: robustness in combinatorial optimization Markus Leitner (VU Amsterdam) - Routing with temporal dependencies Martin Schmidt (Trier University) - Theory and Algorithms for Linear and Mixed-Integer Bilevel Optimization The school is part of the activities of the ENOG (European Network Optimization Group). Potential participants will be invited to submit their CVs to the address netopt@ciencias.ulisboa.pt no later than October 31. Further information will be available in the webpage https://netopt2027.campus.ciencias.ulisboa.pt