How can learning styles best be measured? Reid's (1984) Perceptual Learning Styles Preference Questionnaire has been widely used in ESL/EFL research to investigate learning styles. Previous research revealed concerns with the reliability and validity of the PLSPQ, leading the researchers to devise a new Learning Styles Indicator (LSI), based on the PLSPQ, and tested on different populations. From the results of this testing arose additional concerns regarding the construction of the PLSPQ/LSI statements themselves. How then can learning styles instruments best be validated? Interviews of graduate students in a Master's in TESOL degree program revealed that quantitative means alone are insufficient to ascertain the effectiveness and usefulness of a learning styles instrument, particularly in the case of non-native speakers. A triangular approach utilizing a questionnaire, semi-structured oral interviews, and participant observations presents a fuller picture of instrument validation.