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 | 19 | 14 | 2 | 3 | 30 | 12 | 18 | 44 |
| 2 | Atalanta BCAtalanta | 18 | 13 | 2 | 3 | 43 | 20 | 23 | 41 |
| 3 | Inter Milan | 17 | 12 | 4 | 1 | 45 | 15 | 30 | 40 |
| 4 | Lazio | 19 | 11 | 2 | 6 | 33 | 27 | 6 | 35 |
| 5 | Juventus | 18 | 7 | 11 | 0 | 30 | 15 | 15 | 32 |
| 6 | Fiorentina | 18 | 9 | 5 | 4 | 31 | 18 | 13 | 32 |
| 7 | Bologna | 17 | 7 | 7 | 3 | 25 | 21 | 4 | 28 |
| 8 | AC Milan | 17 | 7 | 6 | 4 | 26 | 17 | 9 | 27 |
| 9 | Udinese | 19 | 7 | 4 | 8 | 23 | 28 | -5 | 25 |
| 10 | Roma | 19 | 6 | 5 | 8 | 26 | 24 | 2 | 23 |
| 11 | Torino | 19 | 5 | 6 | 8 | 19 | 24 | -5 | 21 |
| 12 | Empoli | 19 | 4 | 8 | 7 | 18 | 22 | -4 | 20 |
| 13 | Genoa | 19 | 4 | 8 | 7 | 16 | 27 | -11 | 20 |
| 14 | Parma | 19 | 4 | 7 | 8 | 25 | 34 | -9 | 19 |
| 15 | Hellas VeronaHellas Verona | 19 | 6 | 1 | 12 | 24 | 42 | -18 | 19 |
| 16 | Como | 18 | 4 | 6 | 8 | 20 | 30 | -10 | 18 |
| 17 | CagliariCagliari | 19 | 4 | 5 | 10 | 18 | 32 | -14 | 17 |
| 18 | Lecce | 19 | 4 | 5 | 10 | 11 | 31 | -20 | 17 |
| 19 | VeneziaVenezia | 19 | 3 | 5 | 11 | 18 | 32 | -14 | 14 |
| 20 | Monza | 19 | 1 | 7 | 11 | 17 | 27 | -10 | 10 |
| > Serie A Full Table | |||||||||
