This study evaluates the impact of in-service education and training on Tanzanian foreign language teachers learning. The in-service training focused on equipping teachers with knowledge and skills in competency-based language teaching. The qualitative research approach and the Most Significant Change (MSC) technique were used to guide the research process. The data were collected from Manyara and Kilimanjaro Regions. Twenty-one respondents were purposely selected and interviewed in a one-to-one unstructured interview. Information from the interview was managed using ATLAS.ti and thematically analyzed using a thematic approach. The finding indicated that the in-service training effectively impacted teachers learning on subject knowledge, general knowledge, and pedagogical content knowledge relating to competency-based language teaching. Therefore, the Ministry of Education and Vocational Training and other education stakeholders need to sustain the knowledge gained to reflect it in English language teachers’ classroom practice by providing follow-up and support. Moreover, the discrepancy in some facets of knowledge gained and limited change stories related to the planning, teaching, and assessing grammar call for more in-service training so that teachers gain the correct information and appropriately teach and assess grammar by associating it with functional usage.

Purpose In Tanzania, in-service training was implemented to facilitate teachers understanding and implementation of the competency-based curriculum in the English language. This study aims to evaluate whether or not the in-service training was effectively planned to achieve its goals. Design/methodology/approach The study used a narrative research design that focuses on analysing the story of a particular event, object or programme as it occurred in a specific social context. Thirty-two purposefully selected respondents were interviewed, and data were analysed using the thematic approach. Findings The study found strengths and weaknesses in the in-service training planning process. The strength included coherence between the need for in-service training and country priority. Moreover, collective participation was promoted since all trainees were English language teachers. Perceived weaknesses included a lack of coherence between training objectives and teachers’ actual needs. Equally, collective participation was limited because trainees taught mixed grades with varied work environments and experiences. Besides, heads of schools were not involved in training planning. Even those tasked with a lead role in cascading training to untrained teachers lacked the confidence and competence to do so. Originality/value The study contributes to the body of knowledge by uncovering weaknesses associated with in-service planning in Tanzania. The study calls upon the future planners of in-service training to consider the elements of effective in-service training during the planning and ensure that the views of all stakeholders at the macro and micro levels are assessed for quality programme implementation and better results.