Although a wealth of pedagogical material exists for most aspects of trumpet performance, there is a comparatively small body of such material devoted to intonation. In addition, while there is general agreement that good intonation is essential to a successful performance, there is no widely accepted methodology for helping students achieve it. This study first identifies the factors that influence trumpet intonation and explores the reasons why intonation receives less pedagogical emphasis than other performance elements. It continues with an examination of how intonation is addressed in existing published materials. This summary of the approaches used in pedagogical publications is compared with methods practiced in applied trumpet studios, based on interviews with respected trumpet professors in major music schools and conservatories. The goal of the study is to define and highlight issues that can help provide a clear focus for future attempts to improve the way intonation is taught and studied.