The present study sought to investigate the relationship between parental responsiveness and behavioural adjustment among pupils in primary schools in Kisii central Sub-County, Kenya. The study was guided by the Object relations theory and supported attachment theory. The study adopted mixed method approach in which the embedded research design was used. To obtain the sample for the study, the study used cluster sampling, stratified sampling and simple random sampling techniques. The unit of analysis included 218 primary schools. The target population comprised of 14876 pupils, 10582 parents, 229 deputy head teachers and 218 guidance and counselling teachers. The sample size for the study consisted of 374 pupils, 30 parents, 30 deputy head teachers and 30 guidance and counselling teachers. The study also employed questionnaires and interview schedules to gather data. The study adopted the triangulation approach to measure the validity of the instruments. Split half method was also used to establish the reliability of instruments whereby the correlation coefficient value of .808 was established. In analysing qualitative data, the study used thematic analysis while descriptive and inferential statistical techniques were used to analyse quantitative data. The study established that there was statistically significant positive (r=.595, n=356, p<.05) relationship between parental responsiveness and pupils’ overall behavioural adjustment and all the five aspects of behavioural adjustment (conduct problems, peer relationship problems, emotional symptom, hyperactivity and pro-social behaviours). The study further established that parental responsiveness alone accounted for 35.4% of the variation in the overall behavioural adjustment among the pupils of class 7 and 8, as signified by coefficient R2 of .354. On the same note, if the parental responsiveness increases by one unit then level of overall behaviour adjustment would improve by .287 units; this is a considerable effect from one independent variable. The results further indicated that most of the children’s problematic behaviour outcomes were as a result of parents frequently ignoring children’s needs. The study also established a link between perceived parental emotional support, trustworthiness, understanding, physical support and sensitivity to children’s needs and children’s positive behavioural reputations, competencies and self-perceptions.