Hueniken K, Douglas CM, Jethwa AR, et al. - Given that significant financial toxicity may be faced by patients receiving treatment for head and neck cancer (HNC), researchers sought to construct as well as validate the Financial Index of Toxicity (FIT) tool. They used literature review to generate items. Items were based on expert opinion. After the removal of items with factor loadings of a magnitude <0.3 in exploratory factor analysis and inverse correlations (r < 0) in test‐retest analysis, the FIT was built with the retained items. Experts administered the FIT to 430 patients with HNC at 12 to 24 months post-treatment. The instrument was shown to have good internal consistency as well as satisfactory test‐retest reliability. The observed correlations between the FIT and Social Difficulties Inventory Money Matters subscale were mild to strong, as shown by concurrent validation. Inverse correlation of FIT scores with baseline household income and positive correlation with lost income were identified. Overall, findings revealed that the 9‐item FIT not only showed internal and test‐retest reliability but also concurrent and construct validity. To further establish its responsiveness as well as generalizability, there is a requirement for prospective testing in patients experiencing HNC who were managed at other facilities.