A 61-year-old man is being questioned by detectives after red paint was sprayed on mosques and businesses across west London as well as the Palestinian Mission in Hammersmith.
The suspect was arrested in Ealing on Monday on suspicion of racially aggravated criminal damage and taken into custody where he remains, the Metropolitan Police said.
Detectives have described the “linked” series of incidents as “Islamophobic”.
The alleged offences are said to have taken place in the boroughs of Hammersmith and Fulham and Ealing on 12 separate occasions between October 16 and November 18.
Detective Superintendent Figo Forouzan, who is leading the investigation, said: “Hate crime has no place in London. Its effects run far deeper than property damage, and the impact on victims can linger beyond the removal of the paint.
“Officers have been working incredibly hard to identify the individual responsible for these offences and provide the relevant support and reassurance to those affected.
“The victims are being supported by dedicated faith officers, and neighbourhood teams have changed their patrol times and routes to provide additional reassurance.”