The ability of Mandarin learners to express emotion in Mandarin has received little attention. This study examines how English L1 users express emotions in Mandarin and how this expression differs from that of Mandarin L1 users. Scenarios were adopted to elicit joy, anger, sadness, fear, and neutrality. Both groups articulated anger, joy, and fear with a high pitch. Both groups also employed high intensity for anger and joy and low intensity for sadness and fear. Learners generally employed larger F0 ranges than native speakers, particularly for anger and fear. Learners articulated level tones with lengthened duration and contour tones with shortened duration, affecting the correctness of the portrayal of emotions. Learners used a similar intensity range for all emotions, whereas native speakers tended to vary the intensity with different emotions. The results have implications for teaching Mandarin as a second language with special reference to prosodic naturalness in expressing emotions.