In sociometric research tradition, popularity is defined as the degree to which children are liked or accepted by their peers. However, research indicates that two definitions of popular students should be distinguished: (1) popular students as those students who are well liked by many and disliked by few peers, and (2) popular students as those students who are described as popular by their peers. The main purpose of the present study was to examine the relationship between sociometric and peer perceived popularity in Slovenian students of different grades of elementary and secondary school. Additionally, the age differences in the relationship between sociometric and peer perceived popularity were examined. Another purpose of the study was to investigate the differential relationships between concepts of popularity and some students' characteristics. The participants were 321 boys and 329 girls who ranged from the 5th grade of elementary school (the mean age 11.04 years) to the 3rd grade of secondary school (the mean age 17.02 years). The results of this study confirm previous findings that peer perceived popularity is a construct that is distinct from sociometric popularity. There are some substantial differences in relations between indices of perceived popularity and sociometric indices between elementary school students and secondary school students--i.e. between early adolescents and middle to late adolescents. It seems that perceived popularity and sociometric popularity are rather similar constructs in elementary school students, whereas in secondary school students they become almost unrelated to each other. Based on these findings, the terminological issues are discussed and some conclusions are made.