This study aimed to test the adequacy of a quantitative measure of our qualitatively developed Patient Typology—categories of older adults' attitudes towards medicines and medicine decision‐making—and identify characteristics associated with each Typology. We conducted secondary data analyses of a subset of survey item measures of adults (≥65 years) who were members of online survey panels in Australia, the United Kingdom, the United States and the Netherlands (n = 4688). Multinomial logistic regression analyses assessed associations between demographic, psychosocial and medication‐related measures. Mean age was 71.5 (5), and 47.5% of participants were female. Factors associated with an increased likelihood of identifying with Typology 1 ‘Attached to medicines’ over Typology 2 ‘Open to deprescribing’ were higher positive attitude towards polypharmacy (RRR = 1.12, p = <0.001) and higher need for certainty (RRR = 1.11, p = 0.039). Factors associated with an increased likelihood of identifying with Typology 3 ‘Defers (medication decision‐making) to others’ over Typology 2 were older age (RRR = 1.47 per 10‐year age increase, p = <0.001) and a decreased likelihood of prior deprescribing experience (RRR = 0.73, p = 0.033). This study provides validation of the Typology with large samples from four countries, with the quantitatively‐measured typologies generally aligning with the qualitatively derived categories. Our Patient Typology measure provides a succinct way researchers can assess attitudes towards deprescribing.