Our nightgowns have a relaxed, easy fit. The best way to determine your size is by measuring your bust. Note if you are tall and slender, you may want to size up for more length in the smaller sizes. (See model Angelica below--she's technically a Small but because she is 5 ft 7, the Medium gave her more length.)
Here are some example size matches:
Kathy (Krista's mom!): 5 ft 2, 32.5 inch chest, 33 inch waist, 40 inch hips. Small
Georgina: 5 ft 3, 37.5 inch chest, 38 inch waist, 43 inch hips. Medium
Angelica: 5 ft 7, 32 inch chest, 27 inch waist. Medium
Edna: 5 ft 9, 44 inch chest, 37 inch waist, 44 inch hips. Extra Large
Ashley: 5 ft 10, 38D chest, 37 inch waist. She's wearing Extra Large in the Year of the Tiger photos but 1X would also be a good size and smooth out the fall of the garment in the back.