Аннотация
The International Olympiad in Informatics (IOI) is an annual international informatics competition for individual students at schools for secondary education from various invited countries, accompanied by social and cultural programmes.We present a report on the 27th International Olympiad in Informatics, July 26 -August 2, 2015, Almaty, Kazakhstan (IOI'15), organized by the Ministry of Education and Science of the Republic of Kazakhstan, Republican Scientific and Practical center "Daryn", al-Farabi Kazakh National University and supported by Mayor of Almaty and Mayor of Almaty region.IOI'15 established a new IOI record with 322 contestants from 83 countries, participated in IOI'15 and awarded by 161 medals (27 gold, 55 silver and 79 bronze), Jeehak Yoon from the Republic of Korea is absolute winner of IOI'15.At IOI'15 Java was first time introduced as IOI official programming language.In this report we pointed attention on issues happen as well as things that done well.