One of the main significant purposes of learning the English language is the need to have an effective communication allowing for exchange and transmitting information. As a basic form of human communication that allows people to connect, communicate, and share experiences with one another is writing skill. Through practicing trainable abilities like speaking, and writing, adaptation skills are required to overcome issues that develop in unfamiliar environments. Learners must be cognitively flexible to reconstruct and adjust to these situations' demands. This study aims at looking into the level of cognitive flexibility and writing abilities of Iraqi EFL university students. It also seeks to determine how these two variables are related. It is a correlational one, through which two instruments are employed (a questionnaire for measuring cognitive flexibility, and an essay writing for testing writing). After their validity and reliability have been confirmed, the study's instruments are administrated to 400 participants chosen at random from three English departments at Universities of Babylon, Thi- Qar and Kirkuk. The statistical manipulation of the data shows that the participants have a moderate level at cognitive flexibility whereas a good level at writing productivity. In addition, the results have shown that there is a statistically significant relationship between the participants’ writing proficiency and their level of cognitive flexibility.