Professional Learning Communities are hailed as efficient tools for fostering collaboration among teachers and improving achievement among students. This qualitative case study seeks to understand the transition of an informal collaborative group (Community of Practice/CoP) to a formal collaborative group (Professional Learning Community/PLC). This case study utilized semi-structured interviews of three biology teachers who comprise the Biology teacher PLC at a suburban high school in a West South Central state. The participants composed the informal collaborative group, experienced the transition to a professional learning community, and now comprise the formal collaborative group (PLC). The interviews were audio-recorded and then transcribed, verbatim, for data analysis. The researcher coded the interview transcriptions and looked for emergent themes from the data. The study concluded that the transition to the PLC was initiated and facilitated by the school’s administration and that the most arduous task in implementation was providing a common plan during which they could meet as a PLC. The participants reported feeling that their PLC is more efficient and easier to collaborate in comparison to their experiences in the CoP.