| Cover | Oct. 25, 2021 |
| Cover [Abstract] | |
| Document Type | 8-K |
| Document Period End Date | Oct. 25, 2021 |
| Entity Central Index Key | 0000916907 |
| Entity File Number | 000-23406 |
| Registrant Name | SOUTHERN MISSOURI BANCORP, INC. |
| Entity Incorporation, State or Country Code | MO |
| Tax Identification Number (TIN) | 43-1665523 |
| Entity Address, Address Line One | 2991 Oak Grove Road |
| Entity Address, City or Town | Poplar Bluff |
| Entity Address, State or Province | MO |
| Entity Address, Postal Zip Code | 63901 |
| City Area Code | 573 |
| Local Phone Number | 778-1800 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Title of 12(b) Security | Common Stock, par value $0.01 per share |
| Trading Symbol | SMBC |
| Security Exchange Name | NASDAQ |
| Emerging Growth Company | false |
| Amendment Flag | false |
