The organisation has today published recommendations for managers and HR professionals on supporting bisexual employees and developing bisexual inclusive policy and procedures.
Bisexual People in the Workplace, supported by the Home Office, shows how the experience of bisexual staff is often distinct from lesbian and gay employees and what employers can do to address this.
One finding is that bisexual employees often feel invisible in the workplace, with no visible bisexual role models in their organisations.
Equality and diversity initiatives concerned with sexual orientation - such as network groups - also exclude bisexual staff as lesbian and gay colleagues can have misconceptions about bisexuality.
The findings highlight the difficulties bisexual employees face when trying to be out in the workplace. Also featured are practical examples of good practice currently being developed by some of the 500 employer members of Stonewall's Diversity Champions programme.
Stonewall recommends employers nominate a bisexual representative in the workplace, and do more to promote awareness of bisexuality at induction and diversity training. Employers have also been warned to amend bullying and harassment policies to take bisexual staff into consideration.
David Shields, Stonewall's director of workplace programmes, said: "Bisexual employees, like all staff, perform better when they can be themselves. For many bisexual employees it can be difficult to be open about their sexual orientation. If relevant policies don't cover bisexual issues, or sexual orientation networks exclude bisexual people, this contributes to bisexual invisibility in the workplace.
"There are a number of practical actions employers can take to include bisexual staff at work. By making workplaces more inclusive everyone benefits and employers can make the most of the talent they have."
