Background: Adolescence is a crucial developmental stage marked by rapid physical, cognitive, and emotional changes that can significantly influence mental health. Psychological well-being during this period determines how effectively adolescents cope with stress, build relationships, and maintain self-esteem. Understanding the factors that affect their psychological well-being is essential for promoting healthy emotional development and preventing future mental health issues. Objective: The study aimed to assess the level of psychological well-being among adolescents and to examine its association with selected socio-demographic variables such as age and gender. Methodology: A descriptive research design was adopted for the study. The sample consisted of 100 adolescents from various areas of Lucknow, selected through purposive sampling. Data were collected using a semi-structured interview schedule and the Birleson Psychological Well-Being Scale for Adolescents (1980), a standardized self-report tool assessing emotional and psychological well-being. Statistical analysis was performed using SPSS-20, applying frequency, percentage, mean, standard deviation, and t-test to determine significance. Results: The findings revealed that 72% of respondents were in the 15-17 years age group, and 52% were males. Most participants demonstrated moderate to good levels of psychological well-being, with a mean score of 32.93 ± 2.53. Significant differences were found in psychological well-being with respect to age (t = 38.115, p = 0.000) and gender (t = 29.475, p = 0.000), indicating that both variables influence adolescents’ emotional adjustment. Conclusion: The study concluded that psychological well-being among adolescents is significantly influenced by age and gender. Older adolescents showed better emotional stability, while females exhibited higher emotional vulnerability. Supportive family environments, parental education, and occupational stability were found to positively impact adolescent mental health. The findings highlight the need for early mental health screening, school-based counseling, and parental involvement programs to enhance psychological well-being among adolescents.