In the U.S., the song ranked among Cashbox's Top 100 singles of 1968, where it hit the No. 1 position the week ending August 3, 1968.[3]
"Lady Willpower" went No. 2 on the Billboard Hot 100 in 1968 (behind "Grazing in the Grass" by Hugh Masekela).[4] and reached No. 26 on the Easy Listening chart.[5] The song was the No. 34 song on the Billboard Year-End Hot 100 singles in 1968.[6]
Outside the US, "Lady Willpower" reached No. 5 on the UK Singles Chart during the year.[7]
"Lady Willpower" also peaked at #4 on the Kent Music Report (KMR)[8] Chart in Australia, spending 16 weeks on the KMR Top-100 after entering the chart on the 22nd June 1968.