Mamadou Sylla Diallo (born 20 March 1994) is a Senegalese professional footballer who plays as a forward for Spanish club Real Valladolid.

[2] He subsequently represented CE Mataró and RCD Espanyol, and made his senior debuts with the latter's reserve team in 2013, in Segunda División B.

On 27 March 2015 Sylla joined Segunda División strugglers Racing de Santander on loan until the end of the campaign, as a short-term replacement to injured Mamadou Koné.

Sylla made his debut in the main category of Spanish football on 27 September 2015, coming on as a second-half substitute for Víctor Sánchez in a 0–3 away loss against Deportivo de La Coruña.

[6] On 3 December, he scored his first goal for the team, coming off the bench to open a 1–1 draw at Levante UD in the first leg of the last 16 of that season's Copa del Rey.