Background: Strong classroom management skills are necessary for students' academic and behavioral success (e.g., Korpershoek et al., 2016), and group contingencies are an effective strategy teachers can use to help improve classroom behaviors (Little et al., 2015; Maggin et al., 2012). CW-FIT is one group contingency intervention that helps increase student academic engagement and on-task behaviors across a variety of students and settings (e.g., Wills et al., 2010; Kamps et al., 2015). CW-FIT uses several key features, including (a) teaching appropriate behaviors, (b) increasing teacher praise, (c) reducing attention to inappropriate behaviors, and (d) rewarding student groups for meeting behavioral goals. CW-FIT has been extensively researched across populations and settings and has been found to help improve student behavior, increase teacher praise, and lower levels of teacher reprimands, allowing for increased instructional time and, eventually, improvements in academic achievement. Purpose: Despite the large research base for CW-FIT, a meta-analysis of effects has not been conducted, thus the purpose of this study was to conduct a systematic review and meta-analysis of CW-FIT. Specifically, the following research questions guided this study: (RQ1) What are the study characteristics of the CW-FIT literature base? (RQ2) What are the effects of CW-FIT implementation on student on-task and disruptive behaviors? (RQ3) What are the effects of CW-FIT implementation on teacher praise and reprimands? We hypothesized that across studies, CW-FIT would significantly increase on-task behaviors, decrease disruptive behaviors, increase teacher praise, and decrease teacher reprimand use. Research Design & Methods: We used systematic review and meta-analysis methods and procedures aligned with current recommendations (e.g., Borenstein et al., 2009; Cooper et al., 2009). We searched all available databases using the following terms: CW-FIT, classwide function-related intervention teams. When reviewing studies for inclusion, limitations were placed on written language of the study (i.e., English), intervention (i.e., CW-FIT), and research design (i.e., an empirical study). Qualitative studies were included for the purpose of the systematic review; however, none were found during the search. The team conducted title and abstract screening, full-text screening, and data extraction for both the systematic review and meta-analysis. Intervention CW-FIT is a group contingency intervention used to shape appropriate classroom behaviors through specific praise, effective feedback, and team-based rewards. There are four key components: (a) lessons and precorrects; (b) teaming; (c) goals, points, and praise; and (d) rewards. Behavioral lessons are taught prior to implementing CW-FIT, and pre-corrections are used at the beginning of each session to remind students of the expected behaviors. Teachers divide students into teams that are easy to discern throughout the class period. Teams usually consist of 3-6 students who work together to earn points by engaging in the expected behaviors. Challenging but achievable point goals are set prior to each CW-FIT session based on familiarity with CW-FIT and the length of the class period. The teacher uses a fixed interval timer (e.g., 3 minutes) as a cue to scan teams for appropriate behaviors, provide points and behavior-specific praise to teams engaged in these behaviors, and give brief corrective and encouraging feedback to teams not engaged in the expected behaviors. At the end of the session, teams who meet the point goal receive a predetermined brief (e.g., 5-minute) reward. Rewards are meant to be motivating for students and low-effort for teachers, such as quick dance breaks or classroom free time. Data Collection and Analysis: Study characteristic data were extracted using a Qualtrics form and included information on teacher and student participants, CW-FIT use, and study design. Studies eligible for the meta-analysis were split into group and single-case designs for data extraction. For group designs, we collected reported effect sizes, means, standard deviations, and coefficients from hierarchical linear modeling as provided. We further separated data by outcome measure domains (e.g., student on-task, teacher praise) and measurement unit (i.e., target student, classwide, teacher). For single-case design studies, we extracted data for each outcome using WebPlotDigitizer (Rohatgi, 2022) and exported data to Excel, where we organized it by outcome domain and measurement unit as for group designs. We calculated Hedges' g and the variance of g using the Campbell Collaborative calculator (Wilson, n.d.) for group design studies. For single-case designs, we calculated the design-comparable or between-case standardized mean difference as Hedges g based on a multilevel modeling approach for multiple-baseline and withdrawal/reversal designs (see Pustejovsky et al., 2014) using the scdhlm (Pustejovsky et al., 2024) package in R. Across studies, we calculated 65 effect sizes. Due multiple outcomes within each study violating assumptions of independence, we used robust variance estimation models in the robumeta (Fisher et al., 2023) R package. Results: The systematic review yielded 34 individual studies. Ten studies were dissertations, with six later published in peer-reviewed journals. Most studies (k=20) were conducted in elementary settings, followed by middle schools (k=9). Studies primarily took place in general education classrooms (k=22) and were largely single-case design (k=26). After combining group and single-case effect sizes for the meta-analysis, results by outcome were as follows: student on-task behaviors g=1.88 (SE=0.15, p<0.001); student disruptive behaviors g=-2.01 (SE=0675, p<0.05); teacher praise g=1.48 (SE=0.26, p<0.001); and teacher reprimands g=-0.70 (SE=0.14, p<0.01). Results by outcome unit were as follows: target students g=1.11 (SE=0.21, p<0.001); classwide g=2.19 (SE=0.19, p<0.001); teachers g=1.19 (SE=0.16, p<0.001); note the directionality of disruptions and reprimands were recoded in these models such that a positive effect size represented a therapeutic directional change in the outcome to facilitate effect size calculation. Conclusions: This systematic review and meta-analysis provide strong evidence of the effectiveness of CW-FIT across target student, classwide, and teacher behavioral outcomes. These results align with a rigorous What Works Clearinghouse review (2023) further indicating CW-FIT's inclusion as an evidence-based practice. Despite including dissertations, the potential remains for unpublished studies that were not found during the systematic review. Future research suggestions include assessing the quality of studies included in this meta-analysis, along with conducting moderator analyses to assess differences by settings.