The 25-year-old has penned a five-year contract with the club, for a reported fee of €7m (£5.53m).
Bonaventura has been capped once by the Italian national side and scored eight goals in Serie A last season.
He has become the club's third signing of the week, following the arrivals of Fernando Torres and Marco van Ginkel on loan from Chelsea.
Restore Data
| Team | P | W | D | L | F | A | GD | PTS | |
| 1 | Napoli | 20 | 15 | 2 | 3 | 32 | 12 | 20 | 47 |
| 2 | Inter Milan | 18 | 13 | 4 | 1 | 46 | 15 | 31 | 43 |
| 3 | Atalanta BCAtalanta | 20 | 13 | 4 | 3 | 44 | 21 | 23 | 43 |
| 4 | Lazio | 20 | 11 | 3 | 6 | 34 | 28 | 6 | 36 |
| 5 | Juventus | 20 | 7 | 13 | 0 | 32 | 17 | 15 | 34 |
| 6 | Fiorentina | 19 | 9 | 5 | 5 | 32 | 20 | 12 | 32 |
| 7 | AC Milan | 19 | 8 | 7 | 4 | 29 | 19 | 10 | 31 |
| 8 | Bologna | 18 | 7 | 8 | 3 | 27 | 23 | 4 | 29 |
| 9 | Udinese | 20 | 7 | 5 | 8 | 23 | 28 | -5 | 26 |
| 10 | Roma | 20 | 6 | 6 | 8 | 28 | 26 | 2 | 24 |
| 11 | Genoa | 20 | 5 | 8 | 7 | 17 | 27 | -10 | 23 |
| 12 | Torino | 20 | 5 | 7 | 8 | 20 | 25 | -5 | 22 |
| 13 | Empoli | 20 | 4 | 8 | 8 | 19 | 25 | -6 | 20 |
| 14 | Lecce | 20 | 5 | 5 | 10 | 14 | 32 | -18 | 20 |
| 15 | Parma | 20 | 4 | 7 | 9 | 25 | 35 | -10 | 19 |
| 16 | Como | 20 | 4 | 7 | 9 | 22 | 33 | -11 | 19 |
| 17 | Hellas VeronaHellas Verona | 20 | 6 | 1 | 13 | 24 | 44 | -20 | 19 |
| 18 | CagliariCagliari | 20 | 4 | 6 | 10 | 19 | 33 | -14 | 18 |
| 19 | VeneziaVenezia | 20 | 3 | 5 | 12 | 18 | 33 | -15 | 14 |
| 20 | Monza | 20 | 2 | 7 | 11 | 19 | 28 | -9 | 13 |
| > Serie A Full Table | |||||||||
