This study focused on a problem of practice at Mystic River School (MRS), a kindergarten through eighth grade school in an urban district in New England. Schoolwide diagnostic data showed a significant gap between multilingual learners (MLs) and their native English speaking peers in literacy. An analysis of this data, interviews with staff and caregivers, and classroom observations, showed a primary need for training and coaching for teachers in working with MLs. To mitigate this problem a classroom teacher and an English Language Teacher (ELT) co-planned for MLs using a "Looking at Student Work (With Equity in Mind)" protocol. This dissertation studied the effect co-planning will have on the feelings of efficacy of the classroom teacher. This mixed methods study included quantitative data from a survey given before and after the intervention as well as pre and post interviews, observations and transcripts from the co-planning sessions and two classroom observations. Results from this study found that feelings of efficacy were higher by 20% for the classroom teacher after using the protocol and completing a post survey. Feelings of efficacy were also seen in comments through the co-planning sessions and interviews. Although the sample size was small, only one classroom teacher and one English Language Teacher, this study showed promising results for allowing teachers to co-plan in a structured way. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]