Adoption of new curriculum programs is a regular part of education. The problem was teachers lack adequate professional development (PD) and time to acclimate to the implementation of a new English language arts (ELA) curriculum in a school district in the Western United States. The identified gap in the research literature was determining the precise needs of teachers for curriculum implementation. The purpose of this qualitative exploratory case study was to explore the perceptions and opinions of elementary teachers concerning the professional development offered for the implementation of a new ELA curriculum. The theoretical framework drew from Vygotsky's sociocultural theory and the andragogy theory. Key research questions were used to discover the needs of teachers for an ELA curriculum implementation. Data were collected via questionnaires and in-depth interviews from 20 certified elementary teachers. Participants were elementary classroom teachers teaching all subjects, planning to return to the elementary classroom next school year, and having previously participated in a curriculum adoption. The Braun and Clarke thematic analysis model was used to generate codes, and selective coding was used to reduce the number of codes and group into themes. Results of the study regarding a professional development timeline revealed teachers wanted to begin receiving in-person professional development early and to continue regularly and grouped as grade-level peers. Finally, teachers desired to see a model of lesson delivery. Recommendations for future study included expanding the sample to grade levels beyond sixth grade, expanding the geographic area, and researching best model lessons for effective curriculum implementation, producing increased student learning outcomes. [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.]