This document provides guidance on designing questionnaires. It discusses preliminary questions to consider, such as whether to conduct interviews first and how large the sample size should be. It also covers types of questions to include, how questions should be worded, and how to pilot the questionnaire. An example needs analysis questionnaire for Cantonese learners is also included, covering situations where Cantonese would be useful, the learner's current ability level, and activities and experiences that helped study Cantonese.