This study aims to determine whether the Parental Responsiveness Rating Scale (PaRRiS) completed at child age 24–30 months can be used by community child health nurses (CCHNs) to reliably measure the quality of parent–child interactions in practice. Methods A mixed-methods design was used involving CCHNs working in public health settings. Five CCHNs recruited from the North-East of England were trained to use PaRRiS. Thirty parent–child dyads attending their routine 24–30-month check were observed. Nurses rated parent–child dyads during 5 min of free-play using PaRRiS. The free-play sessions were video recorded and rated blind by the first author to the nurse observation. Semi-structured phone interviews were conducted with the five CCHNs once observations of parent–child interactions were complete. Interviews were audio-recorded, transcribed, anonymized and thematically analyzed. Results Two-thirds of participating parents were mothers. Half the families (15/30) were from the 10% most deprived areas based on the English Index of Multiple Deprivation. The average PaRRiS score was 3.03 [standard deviation (SD) = 0.8; all ratings were <5.0]. Reliability between the first author (‘gold standard’) and CCHNs was excellent [Intra-class correlation coefficient (ICC): 0.85; 95% confidence interval (CI): 0.67–0.93]. CCHNs found PaRRiS aligned well with current practice and was acceptable to parents. There was no evidence of a relationship between social disadvantage and PaRRiS scores. Conclusions With further development and evaluation work, PaRRiS could potentially be incorporated into existing universal health services to provide child health nurses with an additional tool for identifying families most likely to be in need of parent–child interaction interventions.