Increasingly, instructional improvement efforts include teacher communities as part of their overall strategy, yet the relationship between teachers' talk and professional learning remains underspecified. Using a discourse perspective on learning, this article compares opportunities to learn (OTLs) in the collaborative conversations of 3 mathematics teacher workgroups. We examined the differences in OTLs in 17 hr of videotaped meetings from 3 groups at different levels of instructional accomplishment in secondary mathematics. Using mixed methods, we uncovered differences in the groups' interactions and found that OTLs were not equally distributed. Instead, teacher groups whose active participants demonstrated the greatest facility with ambitious instruction also had the richest conversational OTLs. We interpret this as an "accumulated advantage" developmental story: Because collaborative work in teaching involves problem posing and the articulation of practice, teachers' conceptions get built into the framing and discussion of pedagogical problems. Accomplished teachers are thus positioned to learn more from talking with colleagues. This analysis contributes to understanding of how OTLs are constituted in teacher workgroups, with implications for making better use of teacher collaboration for professional learning.