Maintaining relationships and interacting socially are essential aspects of children’s occupational performance. Social participation occurs during many childhood occupations such as play and school work. Rather than assessing social skills deficits in isolation, occupational therapists are well placed to assess and treat children with difficulties in social participation during their daily childhood occupations. The existing models of social competence fail to consider or describe the social skills required during learning-related tasks. Therefore, a comprehensive model is needed to guide occupational therapists in understanding social competence during both interpersonal and learning-related social tasks and in specific contexts (e.g., early childhood settings) (Lim & Rodger, 2008). Background and Research Aims: “Social participation” falls within the occupational therapy domain of concern according to the Occupational Therapy Practice Framework (2nd edition) (American Occupational Therapy Association [AOTA], 2008), However, surveys conducted in the United Kingdom, Australia and Canada indicate that there has been limited provision of services for children with poor social skills compared to areas such as sensory processing, motor skill development and visual perceptual skills training (Brown, Rodger, Brown, & Roever, 2005; Howard, 2002; Rodger, Brown, & Brown, 2005). Factors such as a limited knowledge of available tools and limited access to social skills models have hampered occupational therapists’ accurate assessment of social skills (Doble, Bonnell, & Magill-Evans, 1991). This study was conducted in Singapore, where generally there has been limited occupational therapy research, and even less in specific early childhood and school environments. High levels of proficiency in pre-literacy and mathematic skills are expected of young Singaporean children (Ko, 1992; Tan, 2007). With the emphasis on gaining academic skills to be ready for primary education from as early as 3 to 4 years of age, Singaporean children are also expected to demonstrate compliance and ability to sit still while attending to a lesson (Tan, 2007). Hence, it is important to conduct research on specific cultural contexts such as early childhood environments in Singapore. The early childhood literature has begun to differentiate between interpersonal social skills (IPS) and learning-related social skills (LRSS). IPS is needed for maintaining friendships and engaging in play, while LRSS is required for positive classroom behaviours (e.g., staying on task) (McClelland & Morrison, 2003). This research aimed to investigate the validity of the Proposed Model of Social Competence relevant to occupational therapists working with children in early childhood settings. First, this study aimed to investigate whether LRSS and IPS exist as separate unidimensional constructs as suggested in the Proposed Model of Social Competence and second, how these constructs contribute towards young children’s social competence. This research also intended to identify reliable and valid instruments that can be used for the comprehensive assessment of children’s social competence by therapists and educators in early childhood settings. Methodology and Study Findings First, a preliminary content validity study with Singaporean and Australian experts was conducted to investigate whether LRSS and IPS were represented by items from two pre-existing behaviour rating questionnaires (Lim, Rodger & Brown, 2010b). Next, in the main study, 117 young children (aged 3 to 6 years) were assessed using a combination of naturalistic observational tools and behaviour rating questionnaires. The children were observed during free play and school work tasks and their teachers completed two behaviour rating questionnaires regarding the children’s social skills. Rasch analysis and confirmatory factor analysis (CFA) were employed in this study to analyse the data. Results from the content validity study indicated that the two behaviour rating questionnaires selected for inclusion in this study contained items representing IPS and LRSS. In addition, the experts found it clinically useful to consider IPS and LRSS as two separate constructs exhibited by young children. In the main study, IPS and LRSS were found to exist as separate unidimensional constructs, in addition to two other constructs named Compliance and Group Social Interaction which were found to also exist. Scales with acceptable measurement properties were found within the existing social skills assessment tools to measure these constructs. Furthermore, the CFA revealed Social Competence as an underlying multidimensional factor that was composed of the four indicator variables IPS, LRSS, Compliance, and Group Social Interaction. As a result of this study, the Proposed Model of Social Competence was revised. Conclusions and Recommendations Different social skills constructs that contributed to social competence in young children were identified and validated in the study. As Social Competence is a multi-dimensional factor, it is insufficient to assess only children’s interpersonal social skills. The Model of Social Competence-Revised aims to guide occupational therapists and other professionals to consider different types of social skills and elements that may contribute to poor social competence. Depending on the different presenting concerns, practitioners can select specific instruments to assess the different types of social skills identified in this research. Instead of designing new assessment tools that measure newly hypothesised constructs, this study demonstrated a novel approach to extend the validity of existing instruments to measure new constructs (Lim, Rodger & Brown, 2010a). This thesis has extended the extant body of literature by presenting the development, testing, and revision of a proposed theoretical model to assess young children’s social competence within early childhood contexts. This thesis has also contributed by identifying and validating existing assessment tools that can be used to evaluate the different social skills constructs observed in young children within early childhood environments.