"Heaven Knows" is a song by the English rock singer Robert Plant. It was released on 18 January 1988 by Es Paranza Records as the first single from his fourth solo studio album Now and Zen (1988). It reached No. 33 on the UK singles chart and No. 1 on the US Billboard Album Rock Tracks chart. It was Plant's third number-one rock song, following 1983's "Other Arms" and 1985's "Little by Little."