Glottal marking is well described for adult speakers; however, children’s speech has been less documented yet. The present study analysed the appearance of glottal marking in 16 adolescent (16- and 17-year-old) and 16 adult (20- to 45-year-old) speakers’ reading aloud (with an equal number of males and females in both age groups). Data in terms of gender as well as age were compared based on four parameters of frequency of occurrence. The results showed that although the frequency of occurrence of glottal marking in adolescent speech in general was somewhat lower than in adult speech, and the gender-specific differences did not appear yet, the positional triggers for glottal marking were found to affect the frequency of the phenomenon similarly in the two age groups. The results and further research may contribute to the better understanding of both the appearance of glottal marking and the emergence of gender-specific characteristics of speech.