Requirements Engineering (RE) is a critical factor in developing high-quality and successful software, systems and services. The REFSQ working conference series is an established international forum for discussing current and state-of-the-art RE practices, celebrating its 24th year. We are excited to hold REFSQ in Utrecht, returning to the location of the first REFSQ meeting in 1994. We welcome participants to attend REFSQ'18 in the Netherlands!