To explore socially desirable responding in telephone surveys, this study examines response latencies in answers to 27 questions in a corpus of 319 audio-recorded voice interviews on iPhones. Response latencies were compared when respondents (a) answered questions on sensitive vs. nonsensitive topics (as classified by online raters); (b) produced more vs. less socially desirable answers; and (c) were interviewed by a professional interviewer or an automated system. Respondents answered questions on sensitive topics more quickly than on nonsensitive topics, though patterns varied by question format (categorical, numerical, ordinal). Independent of question sensitivity, respondents gave less socially desirable answers more quickly when answering categorical and ordinal questions but more slowly when answering numeric questions. Respondents were particularly quicker to answer sensitive questions when asked by interviewers than by the automated system. Findings demonstrate that response times can be (differently) revealing about question and response sensitivity in a telephone survey.