Validated instruments that measure intimate partner violence (IPV) following separation from an abusive co-parent ("post-separation abuse" (PSA)), are needed to understand and mitigate risks to child health. Items for the Healthcare, Economic, and Legal Post-Separation Abuse and Coercive Tactics (HELP-T) Scale were generated based on qualitative interviews with maternal survivors (N = 33) and expert review. Reliability, construct validity, and concurrent validity were tested in a sample (N = 497) of maternal survivors experiencing PSA in the US. Exploratory factor analysis assessed construct validity, and Cronbach's alpha assessed subscale reliability. Iterative principal factor analysis revealed 3 subscales for 22 items that were labeled (1) Healthcare PSA, (2) Legal PSA, and (3) Economic PSA, and demonstrated strong reliability with Cronbach's alphas from 0.82 to 0.89. The three subscales exhibit strong preliminary psychometric properties and provide insights to help health and legal professionals measure and establish PSA tactics.