"Mercy Mercy Me (The Ecology)" is the second single from American singer-songwriter Marvin Gaye's 1971 album, What's Going On. Following the breakthrough of the title track's success, the song, written solely by Gaye, became regarded as one of popular music's most poignant anthems of sorrow regarding the environment. Led by Gaye playing piano, strings conducted by Paul Riser and David Van De Pitte, multi-tracking vocals from Gaye and the Andantes, multiple background instruments provided by the Funk Brothers and a leading sax solo by Wild Bill Moore, the song rose to number 4 on Billboard's Pop Singles chart and number one for two weeks on the R&B Singles charts on August 14 through to August 27, 1971. The distinctive percussive sound heard on the track was a wood block struck by a rubber mallet, drenched in studio reverb. The song also brought Gaye one of his rare appearances on the Adult Contemporary chart, where it peaked at number 34. In Canada, "Mercy Mercy Me" spent two weeks at number 9.

What's Going On is the eleventh studio album by American soul singer Marvin Gaye. It was released on May 21, 1971, by the Motown Records subsidiary label Tamla. Recorded between 1970 and 1971 in sessions at Hitsville U.S.A., Golden World, United Sound Studios in Detroit, and at The Sound Factory in West Hollywood, California, it was Gaye's first album to credit him as producer and to credit Motown's in-house session musicians, known as the Funk Brothers.