The way we speak to our friends, colleagues, or partners is different in both the explicit context, what we say, and the implicit, how we say it. Understanding these differences is important because it provides additional information that can be used in natural language processing tasks. For example, knowing the relationship between interlocutors can help to narrow the range of topics and improve automatic speech recognition system results. Unfortunately, the lack of corpora makes exploration of this problem intractable. In this work, we release a set of interpersonal relationship labels between conversation participants for the CALLHOME English corpus. We make the labels freely available for download on our website and hope that this effort can further boost research in this area.