Terms weren't disclosed. The transaction is expected to close in March.
Accenture said the deal will strengthen its ability to help clients "rapidly anticipate, detect and respond to cyberthreats."
Symantec’s portfolio of cybersecurity services includes global-threat monitoring and analysis through a network of operations centers, real-time adversary- and industry-specific threat intelligence, and incident-response services.
The cybersecurity-services business includes more than 300 employees worldwide. Six security-operations centers are located in the U.S., the U.K., India, Australia, Singapore and Japan.
Its managed-security-services business is supported by a platform that delivers technical and cyber-adversary-threat intelligence through a portal that clients can customize.
The acquisition "will help Accenture provide flexibility rather than a ‘one size fits all’ approach to managed-security services," said Kelly Bissell, senior managing director of Accenture Security, in a statement.
Accenture, based in Dublin, will be able to provide expertise fine-tuned to individual industries, with tailored global threat intelligence, he said.
Symantec’s cybersecurity-services business is Accenture's latest security-related acquisition. Others include Deja Vu Security, iDefense, Maglan, Redcore, Arismore, and FusionX.
In its 2019 fiscal year, Accenture invested nearly $1.2 billion globally on 33 acquisitions to acquire critical skills and capabilities in strategic, high-growth market areas.
In August, Broadcom, the San Jose, Calif., semiconductor and infrastructure-software provider, had agreed to acquire Symantec's enterprise-security business for $10.7 billion cash.
Accenture shares at last check were off 1.6% to $205.06, while Broadcom was up 0.7% at $315.81.