Twitter hashtags may serve as valuable means for teachers’ professional development. However, given the diversity of hashtag spaces and teacher needs, teachers must assess a given hashtag and compare it to their learning needs and preferences before determining whether it would be helpful. To support this reflection, I examine data associated with 60 Regional Educational Twitter Hashtags (RETHs) during the first six months of 2016 to begin describing the variety of teacher learning-focused Twitter spaces and make distinctions between them. My results indicate that these RETHs vary according to their relative focus on sharing, intimacy of personal connection, and volume of activity, each of which has implications for professional development. The dimensions resulting from this study may prove helpful for teachers, teacher educators, and hashtag coordinators.