This research explored the mental representation of media and digital literacy (MDL) in 242 Mexican high school students through a definitional task based on the natural semantic networks technique. The participants defined ten target concepts related to MDL, using verbs, nouns, and adjectives as definers, and then they rated each definer with a scale from 1 to 10. The smaller the number, the lower the quality of the definer to conceptualize the target, while the higher the rating, the higher the quality of the definer to define it. The participants showed a beginner level in MDL despite their daily navigation through the media space and using some digital devices. These results suggest that simple exposure to information and media technologies does not guarantee the knowledge necessary to use them appropriately and with critical thinking, which points out the need to promote MDL programs in this population, which will empower students to use media and digital tools, with repercussions awareness that its use entails in their academic and social environment.