A vehicle lower section structure includes: a suspension member including a side rail extending in a vehicle front-rear direction, the side rail including a front joint portion and a rear joint portion, the front joint portion being disposed on a front side of the rear joint portion in the vehicle front-rear direction; a securing member joined to the side rail at the front joint portion and the rear joint portion; and a stabilizer secured to the side rail by the securing member. The side rail includes a low-strength portion provided between the front joint portion and the rear joint portion and the low-strength portion has a strength lower than a strength of the front joint portion and the rear joint portion.