Leicestershire Police say they are committed to ensuring that no-one is targeted because of their appearance.
There are currently five nationally agreed hate crime categories but forces can add their own categories.
Greater Manchester Police was the first force to add subcultures as a category, and Leicestershire is the ninth.
Sophie's mother Sylvia Lancaster said people from alternative communities can now be confident they will be taken seriously if they report their concerns to the force.
"It's a wider issue than people realise," said Ms Lancaster.
"It's because alternative subcultures are under the radar, they are not part of the mainstream, and they put up with the abuse and intolerance they face.
"They put up with abuse starting from name calling up to physical abuse."
Read more about the Sophie Lancaster Foundation
Ms Lancaster set up the Sophie Lancaster Foundation to help reduce hate crime, and the charity has previously worked with Leicestershire Police at the Download rock festival.
She said police in some areas do not take the abuse seriously, and she is campaigning for legislation to change so that "lifestyle and dress code" is a hate crime category nationally.
"Very often they are seen as the perpetrators rather than the victims because of the way that they look," said Ms Lancaster.
"We have people [from subcultures] come up to us saying 'Does this mean I have to move to Manchester then?'
"Leicestershire is sending out a signal that it will be taken seriously."
The other police forces to include subcultures as a hate crime category are Durham, East Sussex, Hampshire, Lancashire, Suffolk, Warwickshire and West Mercia.
Darren Goddard, Leicestershire Police's hate crime officer, said: "We are the first force in the region to make these changes and it reflects how seriously we take hate crime and the commitment Leicestershire Police has to ensure that no-one is targeted because of their appearance."
A crime that the victim or any other person perceives to be motivated by hostility or prejudice towards any aspect of a person's identity.
Police forces in England, Wales and Northern Ireland annually monitor five strands of hate crime:
Source: Stop Hate UK
A police force is expanding its hate crime categories to include subcultures after campaigning by the mother of murdered goth Sophie Lancaster.