The purpose of this qualitative investigation was to better understand teaching assistants' (TAs') perceptions of training in a guided inquiry undergraduate general chemistry laboratory context. The training was developed using existing TA training literature and informed by situated learning theory. TAs engaged in training prior to teaching (~25 hours) and attended weekly meetings throughout the year (~60 hours). Assessment of training utilized a constructivist framework to understand TAs' perceptions of training in supporting their implementation of guided inquiry in the laboratory. Participants included 20 graduate TAs and 8 undergraduate TAs of varying teaching experience. Data collection included three open-ended surveys across the academic year and two semi-structured interviews with a purposefully sampled subset of TAs. Data were analyzed using systematic data analysis (Miles and Huberman, 1994). Results indicated different aspects of the training were helpful for different subgroups of participants. For example, going over logistics and completing the experiments were most helpful for TAs with no previous teaching experience while discussing learning theory was least helpful for TAs whose future career goals were research-focused. Analyzing participants' experiences and perceptions through a situated learning theory lens suggested TAs with little prior teaching experience appreciated the authentic experiences (e.g., experiments and grading) provided by the training. The results of the study suggest TA training should address prior experiences, particularly language and teaching, as well as the larger context of research and future careers. Future research will focus on examining how TAs learn within a situated training and how that impacts TA beliefs, practices, and student learning.