The Geriatric Anxiety Inventory (GAI) and its short form (GAI-SF) are self-reported scales used internationally to assess anxiety symptoms in older adults. In this study, we conducted the first critical comprehensive review of these scales’ psychometric properties. We rated the quality of 31 relevant studies with the COSMIN checklist. Both the GAI and GAI-SF showed adequate internal consistency and test-retest reliability. Convergent validity indices were highest with generalized anxiety measures; lowest with instruments relating to somatic symptoms. We detected substantial overlap with depression measures. While there was no consensus on the GAI’s factorial structure, we found the short version to be unidimensional. Although we found good sensitivity and specificity for detecting anxiety, cut-off scores varied. The GAI and GAI-SF are relevant instruments showing satisfactory psychometric properties; to broaden their use, however, some psychometric properties warrant closer examination. This review calls attention to weaknesses in the methodological quality of the studies.