The study titled Influence of Family Processes on Social and Emotional behaviour of Senior Secondary School students in Plateau State, Nigeria. Six (6) specific objectives, six (6) research questions and six (6) null hypotheses were formulated to guide the study. Among the objectives were: to assess the influence of parent-child interaction on social behaviour of Senior Secondary School Students, to establish the influence of parent-child interaction on emotional behaviour of Senior Secondary School Students. The null hypotheses include among others: there is no significant influence of parent-child social interaction on social behaviour of Senior Secondary School Students. Proportionate sampling technique was used to select 384 samples from the population of 91,703 students. Questionnaire and Archival records of students' social and emotional behaviour from the teachers were equally used for the collection of data from the students. A 4-Point rating scale of Very high extent (VHE), High extent (HE), Low extent (LE) and Very low extent (VLE) were used for data collection. Mean and Standard Deviation was used to answer the research questions while Regression analysis was used for null hypotheses. All null hypotheses were tested at 0.05% level of significance. Results indicated that, significant influence exists between parent-child social interaction and social behaviour of Senior Secondary School students in Plateau State (P< 0.05=0.000 at r value .754). It was also found that significant influence exists between parent child interaction and emotional behaviour of Senior Secondary School students in Plateau State (P<0.05=0.000 at r value .699). The researcher concluded that significant influence exists between parent child social and emotional interaction, parental social and emotional conflicts and siblings' social and emotional interaction on social and emotional behaviours of Senior Secondary Schools Students in Plateau State, Nigeria. The researcher therefore recommended among other things that, quality parent- child interaction should be the practice among families in Plateau State.