Decision-making in child protection is a challenging process, with practitioners endeavouring to evaluate and assess factors that inform planning and improve performance. In this regard, assessment tools play a vital role in child protection practices as they facilitate identification of child maltreatment, related risk/protective factors and child outcomes (such as traumatic stress reactions). Over the years, a wide range of assessment tools have become available for use in day-to-day practice and research. Parent-focused examples include the Child Abuse Potential Inventory (Milner, 1990), Child Behavior Checklist (parent and child report;Achenbach & Rescorla, 2001), Difficulties in Emotion Regulation Scale (Charak et al., 2019a) and the Adult Adolescent Parenting Inventory 2.1 (AAPI 2.1; Bavolek & Keene, 2010). There are also numerous outcome measures for children, such as the Trauma Symptom Checklist for Children (Briere, 1996) and the International Trauma Questionnaire (Cloitre et al., 2018;Haselgruber et al., 2020) specifically for ICD-11 post-traumatic stress disorder (PTSD) and complex PTSD in children and adolescents. Such tools can assist in providing additional routes to assessment and intervention planning through triangulation with other sources of data, such as interviews or observations. Thus, ensuring that the use of child protection assessment tools is current and evidence-based is crucial for the protection and wellbeing of our children and families. However, it can prove challenging to keep up with this constantly evolving development of assessments.Therefore, as guest editors, our aim for this special issue is to provide an introduction to the current debates about assessment tools and highlight new developments in this field with an international perspective. With authors and data drawn from Iceland, Northern Ireland, Italy, Switzerland, the USA and the UK, the seven selected articles (i) reflect the importance of conceptualisation of internal and ecological validity of assessment tools, (ii) put forth tools that can be used for examining instances of maltreatment or (iii) present measurement tools that can be useful for clinical interventions and services for child survivors of maltreatment. Also included is a review of an e-learning tool and how effective it was found to be by a practitioner. Several of the papers present promising initial evidence for new psychometric measures or application of an existing tool, which will benefit from later replication or extension studies. Overall, however, we hope that the range of