The charity, which works to empower people with HIV and promote good sexual health, is now a Trusted Information Creator.
To achieve the PIF TICK, organisations must show their health information production process meets 10 key steps.
These include that information is evidence-based, meets health literacy and accessibility needs and is developed with users.
PIF Quality Manager Dan Wills said: “Just 3 years since launch, the PIF TICK now has more than 100 accredited members, with many more organisations currently going through the assessment process.
"We are thrilled Terrence Higgins Trust is the 100th organisation to gain accreditation.
"As the largest voluntary sector provider of HIV and sexual health services in the UK it is at the forefront of the fight to improve the nation’s sexual health.”
View all accredited PIF TICK members here.
Andie Dyer, Production Manager at Terrence Higgins Trust, said: “We’re thrilled our information on HIV and sexual health has been given the PIF TICK.
"Misinformation about HIV is sadly rife online despite the incredible progress we’ve made around treatment which means you can now live a long, healthy life with HIV.
“People who have just been diagnosed with HIV might feel upset, shocked or angry.
"They may have trouble taking in the things they’ve been told.
"It’s critical that people living with HIV and their loved ones can easily access reliable and accurate information in their times of need.
“The PIF TICK mark of quality can give the people accessing our information on HIV and sexual health the reassurance that what they’re reading is 100% accurate – this is crucial with a health condition like HIV which is highly stigmatised.
"Stigma is often a lack of education. If we take the mystery out of HIV with robust and accurate information, we can tackle the fear around it.”
Find out more about the PIF TICK, which is run on a non-profit basis, at piftick.org.uk.