Secondary traumatic stress (STS) is a significant occupational hazard among mental health professionals; however, evidence regarding whether vulnerability differs by professional cadre or gender remains inconsistent, particularly within low-resource mental health systems such as Nigeria's. This study examined professional cadre and gender differences in STS among mental health professionals at the Federal Neuro-Psychiatric Hospital, Barnawa, Kaduna State, Nigeria. A comparative cross-sectional survey design was employed. Using proportionate quota sampling, 150 licensed mental health professionals (112 females and 38 males), aged 25–58 years (M = 40.49, SD = 9.14), were recruited. Data were collected using the Secondary Traumatic Stress Scale and analysed using descriptive statistics, one-way analysis of variance, and independent-samples t-test. The findings revealed no significant differences in STS across professional cadres, F(4, 145) = 1.66, p = .17, η² = .04, or between male and female professionals, t(148) = 0.20, p = .84, d = 0.04. These findings suggest that secondary traumatic stress may be experienced relatively uniformly across mental health professionals irrespective of professional role or gender within this setting. The study highlights the importance of institution-wide staff wellbeing initiatives, including regular psychological support, clinical supervision, and trauma-informed workplace interventions, rather than approaches targeted at specific professional groups.