The injunction has been put in place despite authorities still clueless as to the identity of the group or their whereabouts. The fear is that the group may continue to harass the shareholders with more serious acts.
The Court has ruled that threats to publish shareholders' personal details on any website is prohibited, as is any further contact by letter or approach.
Any person found in breach of the injunction could face prosecution for contempt of court, which is an imprisonable offence.
The pharmaceutical company revealed earlier this week a number of its small private shareholders had received letters demanding that they sell their shares in GSK within 14 days or have their personal details published on the Internet.
"I applaud the resilience of our shareholders in the face of this intimidation. Their courage, integrity and resilience are qualities not recognisable in this small group of extremists who have acted in this deplorable way," said JP Garnier, CEO of >GSK.
"As a Company we have become used to these offensive gestures, but this attack on our shareholders represents a new variation of intimidation and harassment."
GSK have been the subject of intimidation partly because of its profile but also its business links to the Huntingdon Life Sciences research facility. The numerous protests against Huntingdon have often used campaigns targeted directly at individual workers or company shareholders.
Previous campaigns forced Huntingdon to delist from the London Stock Exchange and postpone the US stock exchange listing last year of its parent company, Life Sciences Research.