The Stanford Integrated Psychosocial Assessment for Transplant (SIPAT) is a standardized psychosocial evaluation tool used in liver transplantation (LT) evaluation. We assessed the impact of the SIPAT score and subdomains on transplant waitlisting decisions and post-LT outcomes including immunosuppression (IS) nonadherence, biopsy-proven rejection, andmortality/ graft failure. We conducted a single-center observational cohort study of 1430 patients evaluated for LT. Patients were divided in 2 groups based on a SIPAT cutoff score of <21 or ≥21 (higher SIPAT scores indicate higher psychosocial risk). Regression models assessed relationships between total SIPAT score and domain scores and waitlisting decisions, IS nonadherence, allograft rejection, and death/graft failure. Elevated total SIPAT and SIPAT domain scores were associated not being added to the waitlist (total SIPAT core ≥21 adjusted odds ratio [aOR], 1.78 [95% confidence interval, CI, 1.36-2.33]; readiness score ≥5 aOR, 2.01 [95% CI, 1.36-2.76]; social support score ≥4aOR, 1.50 [95% CI, 1.15-1.94]; psychopathology score ≥7 aOR, 1.45 [95% CI, 1.07-1.94]; lifestyle/substance abuse score ≥12 aOR, 1.72 [95%CI, 1.23-2.39]) and were more likely to experience IS nonadherence as measured by the tacrolimus coefficient of variation (CoV) (total SIPAT score ≥21 aOR, 2.92 [95% CI, 1.69-5.03]; readiness score ≥5 aOR, 3.26 [95% CI, 1.63-6.52]; psychopathology score ≥7 aOR, 1.88 [95% CI, 1.00-3.50]; lifestyle substance abuse score ≥12 aOR, 3.03 [95% CI, 1.56-5.86]). SIPAT readinessscore ≥5 was associated with biopsyproven allograft rejection (aOR, 2.66; 95% CI, 1.20-5.91). The SIPAT score was independently associated with LT listing decisions and IS nonadherence, and the readiness domain was associated with the risk of allograft rejection. These findings offer insights into higher risk recipients who require additional support before and aftertransplantation.