The effects of hydrofluoric (HF) acid etching on the surface mechanical properties of the air and tin sides of an ion-exchanged aluminosilicate float glass are investigated. The hardness and Young's modulus are experimentally measured using nanoindentation. These parameters increase to maximum values at the first 1 min of HF etching before they decrease. Higher values for hardness and Young's modulus are observed at the tin side than at the air side. Changes in the compressive stress, surface structure, and potassium ion concentration with corrosion time are determined to interpret the variation in the surface mechanical properties. The results would be useful in guiding the etching and strengthening process of ion-exchanged float glass.