Interviews are a commonly used data collection method in impact evaluation, and there are many different options to consider when including them. In the context of UNICEF impact evaluations, interviewees may be children, primary caregivers, advocates for children or other key informants. Interviewees can be chosen randomly or purposefully (or using a combination of the two), and they can be interviewed individually or in groups, face to face or ‘virtually’ (i.e., via an online medium). Interviews can be conducted in a structured, semi-structured or unstructured way. Responses can be recorded as audio, video, notes or codes, or using a computer. The range of analysis options includes: developing detailed descriptions of processes or life impacts; generating themes to summarize the data; or not undertaking significant analysis but instead using interview quotes to illustrate quantitative data. This brief outlines key issues to consider in planning interviews for impact evaluation, taking into account the purpose of the evaluation, how interview data aim to complement other data for assessing impact, and the availability of resources. The brief provides specific advice on successfully conducting interviews with children, including how to address the particular ethical issues involved. The efforts required to plan interviews properly and conduct them well should not be underestimated.