The article presents the relationship between the grit factor and the mental well-being of young people recruited from high school students in Podlaskie Voivodeship (n = 275). The study was conducted using the Short Grit Scale (SGS) by A.L. Duckworth, the Psychological Well-Being Scales (PWBS) by C. Ryff and the Cantril’s Ladder of Life Scale. The obtained results indicate significant positive relationships of grit with the current assessment of the quality of life and mental well-being in each of the six dimensions measured with C. Ryff’s PWBS tool (autonomy, environmental mastery, personal growth, positive relations with others, purpose in life, and self-acceptance). Since grit is a construct showing positive relationships with well-being and quality of life and a modifiable one – it can be shaped at an early stage of development – it should be considered as an important element when drawing future educational plans.