In 1919 Lilar attended the State University of Ghent. She studied philosophy and was the first woman to receive a Law degree in 1925. She moved to Antwerp where she became the first woman lawyer. In 1929 she married the lawyer Albert Lilar who would later become a Minister of Justice and Minister of State. After the death of her husband in 1976, she left Antwerp and moved to Brussels in 1977.