Introduction: Numerous studies prove the importance of emotional intelligence in promoting emotional regulation, self-knowledge, empathy and the ability to develop strong social relationships. Some of them highlight the fundamental role of emotional vocabulary, being the good development of this a key factor to name, interpret and regulate our emotions correctly. Method: This study focused on knowing the differences in written expression of short-term emotional vocabulary according to age and gender, in a sample of high school students between 12 and 16 years old, with a total of 442 participants, belonging to the region of Lleida, Spain. Results: The results showed that there was a significant increase in the number of negative words as age increased, as well as a significant decrease in ambiguous words. Differences were also detected in the expression of emotions according to gender, with girls reporting a greater number of both positive and negative words. Discussion and Conclusion: In conclusion, this study proves that there are differences in the expression of emotional vocabulary according to the age and gender of students.