The apparel industry has recently been recognizing the important target market of middle-aged women. The aim of this study was to examine the anthropometric characteristics of US women of 46 to 65 years of age and identify distinctive body shape characteristics of US middle-aged women. A total of 1915 middle-aged women whose ages ranged from 46 to 65 were selected from the SizeUSA database. The age range was divided into two groups: 46-55 and 56-65. Twenty-four body measurements important for apparel development were chosen. Four factors—Girth Factor, Height Factor, Hip Drop Factor, and Bust Drop Factor—accounted for the US middle-aged women’s body measurements. The body shapes were classified into four body shapes, which were Y-Shape in the overweight range, S-Shape in the overweight range, H-Shape in the overweight range, and the A-Shape in obese range. H-Shape, which was the least-defined waist in relation to the bust and hips with a short height, existed more in older middle-aged women than in younger middle-aged women. Y-Shape, S-Shape, and A-Shape existed more in the group of younger middle-aged women than in the group of older middle-aged women. In addition, compared with the younger middle-aged women, older middle-aged women had narrower shoulders, a larger waist, thinner legs, and a longer distance between side neck to bust point. The findings from the current study may be applied in the apparel industry for developing clothing sizing systems for US middle-aged women.