Research has shown that most children with emotional disturbance (ED) are struggling to use communication skills and they may tend to use inappropriate behaviours as a form of communication to disclose their needs. A function-based communication intervention might be an effective approach to decrease inappropriate behaviours of children with ED. The purpose of this single-case multiple baseline reversal design (ABAB) study was to examine the effectiveness of the function-based communication intervention for on-task and disruptive behaviours of an 8-year-old student with ED. Functional behavioural assessment (FBA) was conducted and based on the findings of FBA, a colour-coded communication system, was implemented during reading and math classes. The findings indicated that function-based communication intervention was effective in increasing on-task as well as decreasing disruptive behaviours. Furthermore, the function-based communication intervention improved communication between the teacher and the student that resulted in decreasing disruptive behaviours in a general classroom setting. The generalisability of the findings due to the limited number of participants was an important limitation for this study. Future directions, as well as implications for practices, are discussed.