Background: The Evaluative Linguistic Framework (ELF) was developed to judge the quality of health care texts for patients, based on systemic functional linguistic theory. This approach considers key variables such as context and structure, known to be important for communication. Objective: Our objective was to adapt the ELF to evaluate the quality of self-report questionnaires. Methods: We reviewed the Health Literacy Questionnaire using the ELF. On the basis of these data, we drafted the preliminary version of the Evaluative Linguistic Framework for Questionnaires (ELF-Q) and applied it to English- and French-language versions of two arthritis self-report questionnaires and to Spanish, Dutch, and Turkish versions of an arthritis questionnaire. Results: The developed ELF-Q was found to be effective for evaluating questionnaires in English and in four other languages. It contains nine items with new descriptions and assessment probes. These include overall organizational or generic structure of the questionnaire, metadiscourse (or text about the text), headings, rhetorical elements (function of each "move" or stage of the text in relation to the reader), the writer-reader relationship, technicality of vocabulary, lexical density (proportion of content words in the text), format, and overall judgment. We added assessment responses on a two- or three-point Likert scale to complement the assessment probes and make the intent and meaning of the probes fully explicit for the questionnaire developer or assessor. Conclusions: The ELF-Q is a framework practical to use for the development or assessment of any type of self-report questionnaire. Its application can identify features of a self-report questionnaire that could be improved to optimize its comprehensibility.