| Full Name: | Rolf Axel Ejnar Grönberg |
| Nickname: | "Acke" |
| Birth Date: | 9 May 1918 |
| Birth Place: | Norberg, Sweden |
| Death Date: | 23 April 1988 (aged 69) |
| Death Place: | Stockholm, Sweden |
| Sport: | Greco-Roman wrestling |
| Club: | BK Athén, Stockholm |
| Show-Medals: | yes |
Rolf Axel "Acke" Ejnar Grönberg (9 May 1918 – 23 April 1988) was a Swedish Greco-Roman wrestler, who won the Greco-Roman middleweight division at the 1948 and 1952 Summer Olympics.
Grönberg was raised in Norberg, but moved to Stockholm as a teenager. There he worked as a plumber and masseur, and started wrestling following his elder brothers Fritz and Harald. Besides his Olympic medals he won a world title in 1950, three European Championship medals, as well as 16 national titles between 1944 and 1958.