A recurring debate, in the aftermath of mass atrocity, is whether states should pursue traditional justice through criminal prosecutions or promote peace through alternative mechanisms like truth and reconciliation commissions (TRCs). As scholars have increasingly recognized, however, a multitude of mechanisms meant to deal with past wrongdoings tend to emerge during periods of transition. Nonetheless, due to the legacy of this polarizing debate, additional research is needed on how their work can be mutually re-enforcing in practice. Recent literature has explored whether the sequence of these mechanisms affects long-term outcomes, such as democratic consolidation and respect for human rights, but not how their interaction in practice might contribute to these goals. This Article helps fill that void through an in-depth analysis of the interface between TRCs and traditional justice in the case of Guatemala, a country where over time both arose. In addition to being the first study to gather and analyze the sentences in the cases that resulted in convictions for grave crimes committed during Guatemala’s thirty-six-year internal armed conflict, it bases its findings on over two dozen interviews with judges, prosecutors, and human rights attorneys who have firsthand knowledge of those cases. The study also includes critical insights from the leadership of the TRCs that documented the atrocities committed during that period. What emerged from these primary sources is a compelling example of how these mechanisms can be complementary. On one hand, criminal justice proceedings, or the absence of them, can inform the work of TRCs. On the other hand, although TRCs have traditionally been portrayed as second-rate substitutes for justice, they can serve valuable functions that promote rule of law. For instance, TRCs can act as essential investigators and custodians of evidence in contexts where the state is complicit or directly involved in the underlying atrocities. Additionally, they can be vehicles for liberalization, creating opportunities for alternative voices, norms, and narratives to surface. Indeed, as the case of Guatemala shows, they can transform local judicial decision-making by diffusing international human rights norms and recasting the historical context in ways that influence how judges define and determine responsibility for crimes.