The purpose of this study is to help provide empirically informed insights as to how the Tongan Government teachers’ positive attitudes could be developed and enhanced. In Tonga, the erosion of teacher attitudes, commitment, and professionalism has been recognised (Fua, Manu, Takapautolo, & Taufe’ulungaki, 2007; Matafahi & Fusitu’a, 2009; Taufe’ulungaki, 2012; 2013; Thaman, 1998). This study is an attempt to help address these issues. Within this context, this thesis advocates the need to have an in-depth, and more holistic understanding of Tongan teachers’ professional attitudes: what they are; how they are understood; and how they were formed and strengthened. These are considered initial steps towards informing professional attitudes enhancement activities for Tongan Government school teachers. The findings of this study are an original contribution on the subject of teacher professionalism in terms of teacher professional attitudes, professional attitude formation, and professional attitude strengthening. This study has drawn support from various disciplines and theories, which include Evans’ Professionalism Model (2008; 2010; 2011; 2014), Bronfenbrenner’s General Ecological Model (1979; 1994; 1999), and Hermans and his colleagues’ Dialogical Self Theory (Hermans & Gieser, 2012; Hermans & Hermans-Konopka, 2010). These theories act as theoretical bridges and provide lenses for the exploration of Tongan teachers’ professional attitudes. This study is both constructivist and constructionist in epistemology, with multiple theoretical perspectives, being interpretive, phenomenological, Pacific, and Tongan. A mixed methods research design complemented by a Kakala Mo’onia Pedagogical Positive Deviance methodological approaches were used to understand the Faiako Ma’a Tonga’s (valued teachers of Tonga) professional attitudes. A presurvey, survey and Talanoa Fungani Mo’onia were the major data collection instruments employed. This study relies mainly on a qualitative data collection to answer the research questions. The main findings of the study revealed that the Faiako Ma’a Tonga understood that professional attitudes are life entities intricately linked to teachers’ hearts, they are values and beliefs; good and right behaviours teachers have. Also, professional attitudes have certain features including reflective, persistent, pervasive, transcendental, and positively influential. These features signify professional attitudes are partly spiritual in nature. Professional attitude formation and professional attitude strengthening are processes that are context-related, framed by various complex and inter-related factors, centred around teacher selves, and in many cases mediated by individual(s) of certain professional calibre attitudinally. Typically, they are those who consistently dared to be different in positive ways, hence they possess strong, refined, elegant attitudinal qualities that invite attention, admiration, and imagination (Bronfenbrenner, 1999). Approaches yielding positive energy for teachers are typically what needed to strengthen teachers’ professional attitudes. The concept of Mo’onia is central in this study, from which other original conceptual framework, models, and research method have been derived including the following: Mo’onia Attitude Conceptual Framework-A Tongan Perspective; Kakala Mo’onia Pedagogical Positive Deviance Research Model; Talanoa Fungani Mo’onia research method, Kupesi Lilo-‘o e- To’onga (KLOT) model, and Fale Ako ‘o e Mo’onia Professional Attitudes Enhancement Model. They are also original contributions of this thesis in terms of theory, research, and practice. Key implications of the study include suggestions for a society-wide approach to effective development and strengthening of teachers’ PA, and a strong moral value and belief-based education is critical if Tonga is to be successful in reclaiming and cultivation of teachers’ professionalism and professional attitudes.