We provide a brief description of the development of the Trauma and Suicide Potential Index–5 (TSPI-5) and report on the psychometric properties of scores from the new instrument. The TSPI-5 is designed to assess an individual’s desire to attempt suicide due to experiencing a trauma. We examined the structure of the instrument in two independent undergraduate samples. Study 1 (N = 415) examined the structure of the TSPI-5 using exploratory structural equation modeling. Study 2 (N = 538) reexamined the instrument structure using the same modeling strategy and also examined other validity estimates. Study 1 demonstrated an adequate fit to the sample data (χ2 [1, N = 415] = 215.99, p < .001, comparative fit index (CFI ) = .969, Tucker-Lewis non-normed fit index (TLI) = .939, root mean squared error of approximation (RMSEA) = .319 [90% confidence interval (CI) = .283, .356], p < .001) and suggested evidence for unidimensionality. Study 2 confirmed the unidimensionality of the TSPI-5 as shown by acceptable fit estimates to the sample data, χ2 (5, N = 538) = 80.45, p < .001, CFI = .996, TLI = .99, RMSEA = .17 (90% CI = .140, .200), p < .001. Scale reliability estimates for the TSPI-5 were good in Study 1 (omega = .94) and Study 2 (omega = .96). The TSPI-5 is a brief unidimensional instrument and its scores demonstrated good reliability and validity for assessing suicide-related behaviors due to experiencing a trauma in undergraduate samples.