Anxiety is defined as a multidimensional response with emotional, cognitive, behavioral, and physiological domain with the anticipation of threat. Anxiety negatively interferes with the adaptive functioning of students in elementary and secondary schools and needs to be investigated in detail. The present article examines age and gender differences in representative samples of elementary (4th and 8th grade students) and secondary school students (students of 4th grade in Matura programs). The LAOM anxiety scale that measures anxiety with its components (emotional and cognitive) in students in schools was used. Based on the results of two-way ANOVA important age, gender and the interaction effect is evident in analyzed data. 8th grade female students are more anxious compared to 8th grade male students. The gender differences in 4th grade elementary sample and secondary school sample were not significant. 8th grade students are more anxious compared to 4th grade students, secondary school students are least anxious compared to both elementary school samples. The results are congruent with the findings of the research literature indicating higher anxiety of females when compared to males and higher anxiety of older students when compared to younger students. The paper offers important findings regarding age and gender differences in representative school samples in Slovenia and proposes future research in direction of including different age groups and different measures of anxiety in the analyses.