Jan Węglarz (born 24 September 1947 in Poznań) is a Polish computer scientist.

Member of Polish Academy of Sciences (Polska Akademia Nauk, PAN), member-co-founder of Polish Information Processing Society ("Polskie Towarzystwo Informatyczne", PTI), member of American Mathematical Society, Operations Research Society of America, member of Poznan Chapter of Agder Academy of Sciences and Letters.

Author of 12 monographs in Computer Science, Operation Research, Decision Theory, etc.

In 1991, he was awarded the EURO Gold Medal, the highest distinction within Operations Research in Europe.

He was awarded the decorations of Knight's Cross (1991), Officer (1997) and Commander (2004) in the Order of Polonia Restituta.