This issue is important because research has shown that when perpetrators of violence against women and children enter and maintain involvement in treatment programs, reoffending is reduced in the period after program completion. Evidence of the importance of reducing offenders' denial of their need for treatment is mixed, however. Additional studies are needed in order to determine whether offender motivation to change and ambivalence about the treatment experience play a significant role in predicting treatment effectiveness for these offenders. Research on client reluctance to enter and maintain participation in treatment would benefit from the standardization of terms related to such reluctance. Definitions from the literature are provided for the following terms: engagement, motivation, denial, resistance, readiness, and responsivity. Effective measures are available for the assessment of treatment engagement, therapeutic alliance, and denial among perpetrators of violence against women and children. Stage-of-change measures are also useful in assessing aspects of denial, motivation, and engagement. Evidence of the importance of engagement, alliance, and the avoidance of harsh confrontations has already begun to change practice in the treatment of alcohol and drug problems and is also influencing interventions for sexual offenders who have victimized children. Similar improvements are likely in the treatment of perpetrators of domestic violence against intimate partners and children. 2 tables and 85 references