Introduction: Proper nutrition is important for the health and performance of athletes. However, a lack of knowledge might lead to negative attitude and poor dietary practices. This study aimed to determine the levels of nutrition knowledge, attitude, and practice (KAP) among male gymnasium users in Jordan. Methods:A total of 138 male gymnasium users (21.1±2.8 years) from Jordan were recruited. Their height, weight, body mass index, and age were recorded. The KAP-Sports nutrition questionnaire that contains 25 questions regarding knowledge on basic sports nutrition, 12 questions regarding usual food choices and practices, and 20 questions on attitude towards nutrition and sports-enhancing diet were administrated. Descriptive and Pearson correlation analyses were used to analyse the data. Results: Majority of the participants had moderate knowledge on sports nutrition (77.6%), neutral attitude (84.7%), and fair dietary practice (67.4%). Mean score for knowledge, attitude and practice were 18.1±2.6, 58.8±6.2, and 29.7±3.6, respectively. There was significant, weak correlation between knowledge and attitude (r=0.18, p=0.048), as well as between knowledge and practice (r=0.20, p=0.018). Conclusion: Knowledge is important to affect positive attitude and good dietary practices. However, gymnasium users in Jordan did not have a high level of knowledge that could lead to their positive attitude and good dietary practices. Thus, sports nutrition education is recommended to ensure that adequate and correct knowledge are disseminated to gymnasium users.