This quantitative cross-sectional descriptive study examined the counseling needs of undergraduate students in Nigerian tertiary institutions across four domains: academic, vocational, personal and emotional, and social and adjustment. The target population comprised all full-time undergraduate students enrolled in accredited public and private tertiary institutions across Nigeria's six geopolitical zones during the 2025 to 2026 academic session. Using Krejcie and Morgan's (1970) table, a sample of 652 undergraduates was drawn through multi-stage sampling. The instrument was a structured questionnaire titled the Undergraduate Counseling Needs Questionnaire (UCN–Q), which included the standardized Depression, Anxiety, and Stress Scale (DASS-21). Data were analyzed using descriptive statistics and independent-samples t-tests. The findings revealed that the most prevalent academic counseling needs were examination anxiety management (Mean = 3.42), time management skills (Mean = 3.31), and fear of academic failure (Mean = 3.28). The highest vocational counseling needs were job search strategies (Mean = 3.51), employability skills (Mean = 3.44), and career decision-making (Mean = 3.38). Regarding personal and emotional needs, 78.2% of students reported clinical anxiety, 71.5% reported clinical stress, and 66.6% reported clinical depression. Social and adjustment needs were most acute among newly admitted students, particularly homesickness (Mean = 3.42) and loneliness (Mean = 3.38). The hypotheses tested revealed that newly admitted students reported significantly higher academic counseling needs than advanced-year students (p = 0.0001). In comparison, female students reported significantly higher personal and emotional counseling needs (p = 0.00001) and social and adjustment counseling needs (p = 0.005) than male students. Based on the findings, the study concluded that Nigerian undergraduates experience substantial counseling needs across all domains and recommended mandatory academic counseling for first-year students, career guidance across all year levels, gender-sensitive mental health interventions, and government funding for counseling services.