Scotland Yard, which is investigating the hacking of the telecom giant, said today that the boy's house was searched yesterday. He was arrested on suspicion of Computer Misuse Act offences.
The boy, who cannot be named according to the law as he is a minor, was taken into custody at a County Antrim police station in Northern Ireland and was questioned by detectives from the Police Service of Northern Ireland.
News that the TalkTalk website had been hit by a significant and sustained cyber-attack created a storm last week.
The phone and broadband provider, which has more than four million customers in the UK, said bank details and personal information could have been accessed but stressed that credit and debit card numbers had not been stolen.
The cyber-attack, the third such attack to hit the telecom giant in last one year, had come in the backdrop of several high-profile breaches of personal information in the US.