In discourses and policy documents on school improvement, in-service teacher training is usually stated as one of the key elements to enhance the quality of teaching and overall school functioning (Buchberger, Campos, Kallós and Stephenson, 2000). In order to establish this relationship between teaching and quality, it is necessary to understand how much of this training is transferred to the workplace; transfer is not an automatic effect of the learning process. The aim of this chapter is twofold: (1) to provide a specific model of transfer factors for teacher training in school environments, and (2) to identify how teacher training transfer impacts in-service teacher training in Mexico. In Mexico, training is provided by the Office of the Vice President for Teacher Training, which is responsible for teacher training and education. To evaluate the effectiveness of the training provided by the Office of the Vice President for Teacher Training, we created the Transfer of Learning Factors model based on previous research on teacher training transfer (Ciraso, 2012). The model was based on the new contributions to motivation to transfer (Gegenfurtner, 2012), commitment to transfer (Quesada-Pallarès, 2014), transferoriented training design (Quesada-Pallarès and Ciraso-Calí, 2013), measurement of transfer level (Pineda-Herrero, Quesada-Pallarès & Ciraso-Calí, 2014) and impact (OECD, 2013). This exploratory study collects longitudinal evidence of how and insofar in-service teachers apply what they learnt in training to their teaching practice. The approach involved a non-experimental design. Two questionnaires were used: the CFT at the end of the training activities with a 64 5-point Likert scale items on transfer factors, and the CT, administered three months later, which included 32 5-point Likert scale items on the transfer level, training impacts, and transfer organisation. The CFT questionnaire was administered to a sample of 3,477; 711 nursery, primary and secondary education teachers responded to only one questionnaire whereas 353 responded to both questionnaires (response rate of 9.38%). Validity and reliability were analysed and multiple regression modeling techniques were applied. Our findings show a high learning transfer level perceived by teachers and identify transfer organisation at school as a barrier to teachers’ learning transfer. The final model explained the 27.6% of teachers’ transfer. The model suggested that transfer is more likely to occur if the training activity has a deliberate transfer-oriented design, if teachers’ attitudes towards change are positive, and if the school creates structures and policies to integrate the new learning into their daily practice. Furthermore, when this transfer organisation is established, the positive effect of the school relationships with educational authorities is no longer significant, which allows the centers to be more self-reliant. In addition, results suggest a low training impact on daily teaching practices that could be related to contents and topics developed during training and its relation with teachers’ training needs. These outcomes can be useful for practitioners, teacher training agencies, and managers, since it provides information on how to enhance teachers’ training transfer and how to indirectly evaluate training outcomes in terms of transfer and impact (Pineda-Herrero et al., 2015). On the other hand, outcomes provide new results on factors influencing training effectiveness, which can open up possibilities of deeper research in these areas.