Around 20,000 homes across the UK were without broadband over the weekend, following a fault at a BT exchange.
The outage, which affected a "significant part of the UK" started at around 7pm on Friday night and lasted until Sunday for some.
Engineers worked throughout the night at the Edinburgh-based exchange to resolve the problem, BT said.
"Following a technical fault at an exchange in the Edinburgh area last night which caused disruption to some broadband services, BT confirms that all services have been restored to customers," a spokesman for the telecoms firm added.
BT said telephone services had not been not affected by the problem.