| Sergio Kalaj | |
| Birth Date: | 28 January 2000 |
| Birth Place: | Marino, Lazio, Italy |
| Height: | 1.93 m |
| Position: | Centre-back |
| Currentclub: | Frosinone |
| Clubnumber: | 23 |
| Youthclubs1: | Città di Marino |
| Youthyears2: | –2017 |
| Youthclubs2: | Savio |
| Youthyears3: | 2016–2017 |
| Youthclubs3: | → Roma (loan) |
| Youthyears4: | 2017–2020 |
| Youthclubs4: | Lazio |
| Years1: | 2019–2021 |
| Caps1: | 0 |
| Goals1: | 0 |
| Clubs1: | Lazio |
| Years2: | 2020–2021 |
| Caps2: | 23 |
| Goals2: | 0 |
| Clubs2: | → Grosseto (loan) |
| Years3: | 2021–2022 |
| Caps3: | 17 |
| Goals3: | 0 |
| Clubs3: | Carrarese |
| Years4: | 2022– |
| Caps4: | 11 |
| Goals4: | 0 |
| Clubs4: | Frosinone |
| Nationalyears1: | 2016 |
| Nationalteam1: | Albania U17 |
| Nationalcaps1: | 2 |
| Nationalgoals1: | 0 |
| Nationalyears2: | 2017 |
| Nationalteam2: | Albania U18 |
| Nationalcaps2: | 3 |
| Nationalgoals2: | 0 |
| Nationalyears3: | 2018 |
| Nationalteam3: | Albania U19 |
| Nationalcaps3: | 2 |
| Nationalgoals3: | 0 |
| Nationalyears4: | 2019– |
| Nationalteam4: | Albania U21 |
| Nationalcaps4: | 4 |
| Nationalgoals4: | 0 |
| Club-Update: | 9 June 2024 |
| Nationalteam-Update: | 6 September 2021 |
Sergio Kalaj (born 28 January 2000) is a professional footballer who plays as a centre-back for Italian club Frosinone. Born in Italy, he represents Albania internationally.
On 12 September 2020, he joined Serie C club Grosseto on loan.[1]
On 22 July 2021 he joined Carrarese on permanent basis.[2]
On 13 January 2022, he signed a 4.5-year contract with Frosinone in Serie B.[3]