As survey research in second language acquisition grows in popularity, the adherence to best practices associated with questionnaire quality is critical for a better understanding of factors that influence second language (L2) development. To ensure that a self-report scale targets the construct of interest and does it consistently and accurately, authors of primary research should demonstrate that their instrument possesses acceptable evidence of validity and reliability. To this end, this methodological synthesis focused on the state of scale quality in L2 anxiety and willingness to communicate (WTC) research by examining key methodological issues of quantitative survey research and offering empirically grounded suggestions for future studies. A close examination of 232 peer-reviewed articles that used 385 L2 anxiety and WTC scales demonstrated, among other findings, the lack of evidence for scale content and construct validity. The implications of this study contribute to concurrent attempts at methodological reform in applied linguistics.