| | PF | Signed/Offer Sheet (The Boston Celtics signed F Lamar Stevens.) |
| | C | Signed/Offer Sheet (The Boston Celtics signed C Neemias Queta to a two-way contract. ) |
| | SF | Signed/Offer Sheet (The Boston Celtics signed G-F Svi Mykhailiuk.) |
| | SG | Signed/Offer Sheet (The Boston Celtics signed G DJ Steward to a training camp contract. ) |
| | SF | Waived (The Boston Celtics waived G Justin Champagnie.) |
| | PG | Signed/Offer Sheet (The Boston Celtics signed F Dalano Banton.) |
| | C | Re-Signed (The Boston Celtics re-signed C Mfiondu Kabengele.) |
| | PG | Re-Signed (The Boston Celtics re-signed G JD Davison.) |
| | SF | Signed/Offer Sheet (The Boston Celtics signed F-G Oshae Brissett.) |
| | PG | Declared Free Agency (G JD Davison declared free agency.) |
| | C | Declared Free Agency (C Mfiondu Kabengele declared free agency.) |
| | PF | Declared Free Agency (F Blake Griffin declared free agency.) |
| | PF | Declared Free Agency (F Grant Williams declared free agency.) |
| | C | Traded (The Boston Celtics traded F-C Mike Muscala to the Washington Wizards.) To |
| | SF | Traded (The Boston Celtics traded F Danilo Gallinari to the Washington Wizards.) To |
| | PF | Traded (The Washington Wizards traded F-C Kristaps Porzingis to the Boston Celtics.) From |
| | PG | Traded (The Boston Celtics traded G Marcus Smart to the Memphis Grizzlies.) To |
| | SF | Signed/Offer Sheet (The Boston Celtics signed G-F Justin Champagnie. ) |