The topic of this study has been concretized out of a problem which has been narrowed down and limited on the basis of the theoretical analysis of the teacher selfassessment process, past experience following the research of and the actual teacher selfassessment worldwide and in Croatia as well as on the basis of the objective reflections on the future professional development of teachers and teaching and learning quality. The fundamental concepts such as teacher self-assessment, out-of-school evaluation, quality ensuring system, self-regulatory development, emancipational approach to selfassessment, professional development, competences, teaching and learning, developmental planning, self-assessment modeling etc…. have been explained and defined in the theoretical part of this work. The system and the process of teacher self-assessment have been represented critically. The process of (self-)reflection and self-assessment as an effective tool for improving teaching and the professional development of teachers, especially when the issue is teacher self-assessment, has not been implemented systematically in Croatian schools. Thus it can be concluded that there is a lack of objective, especially operative, researches which would give sufficiently relevant feedback on teacher experiences and the professional competence as well as on their perception of the self-assessment relevance for the advancement of the professional development of teachers and the improvement of teaching and learning to teachers themselves, scientists and school administration. Up to now teacher self-assessment has turned out to be the most efficient in advancing teaching quality that is in teachers' recognition and understanding of their own advantanges and disadvantages according to which aims can be recognized and set as well as feasible personal and common developmental activities can be elaborated. According to a model of dynamic and cyclical process which consists of: planning, application, evaluation and reflection, the need to establish a quality ensuring system in elementary school is imposed. Valid self-assessment gives feedback on teachers and other subjects during teaching, it helps to spot emerging problems and also gives ideas how to solve them. This is the only way how to improve teaching atmosphere, encourage the sense of unity as well as to increase the level of motivation of all the subjects involved. Self-assessment is a compelling factor and a mean of diagnosing the actual state and a corrective tool for teaching quality advancement. The positive connection between teacher self-assessment and the professional development of teachers has been proven. It affects the improvement and development of teaching quality as well as the acquiring and development of students competences. Quality-teacher self-assessment is possible when these principles are applied: future-oriented, the responsability of participants, professionalism, transparency, timeliness and the permanence of the self-assessment process. Teacher self-assessment, as an integral part of the school culture, is the proces of critical evaluation of a teacher's professional development and activity the purpose and the meaning of which is to better understand and to change oneself thus directing one's own professional development and activity. It is a characteristic of a teacher self-assessment process that a teacher himself/herself gives the judgements and ratings of the teacher and his/ her work as well as the other participants of self-assessment process on the basis of the chosen indicators. Teachers, students and school management are not qualified enough to plan, organise, pursue and analise the process of teacher self-assessment. It is an imperative to pay more attention not only to the developing of conciousness and the culture of self-assessment in future but also to the practical action in that direction. Being trained to plan and implement teacher self-assessment is an important component of a teacher's competence. It is preferable that students, expert associates and headmasters take active part in the process of observing and evaluating teaching and learning quality. Self-assessment enhaces self-decison-making and credibility of observing and it advances one's own professional work. By the means of teaching quality indicators and students competences the sucessfulness of teacher's professional work can be established. 36 top ranked indicators have been sorted out to measure contemporary teacher competences, the quality of student competences and teaching and learning quality. The process of teacher self-assessment should undergo critical analysis and evaluation, that is meta-evaluation. By the means of meta-evaluation activities, advancing the process of self-assessment and also by personal professional development and practical work teachers contribute to accelerating the shift from traditional school into ''learning organisation''. Two important developmental priorities which should improve the quality of teacher self-assessment process relate to the forming of a school information system and making the environment more sensitive. The results show that presently only small number of teachers (only 7%) oppose to teacher self-assessment. All the school structures take the firm position that teacher self-assessment should be introduced gradually with all neccessary preparations being made prior to the introduction. Hypothetical-algorithmical model of teaching self-assessment is a significant result of this research. It incorporates all the relevant notions and inovations which have come out of the theoretical analysis and empirical research. The model's hypothesis stresses the need for its exact check and verification in practice as well as the possible content correction of the certain structural components and functional relations between those components which form the entity of the model and its functioning. The model enables every participant in teaching and learning process to evaluate his/ her own activities and the activities of others. Scientifical theory and pedagogical practice will evaluate its real applicational value on the basis of the real utility of the executed research results.