2026
Later action
Uganda Martyrs Day
Public Martyrs’ Day celebrations for 2026 were postponed because of Ebola-outbreak risk, with a later celebration date to be communicated; the notice does not itself rewrite the s…
Evergreen date guide
What is celebrated on May 17?
See the observances and verified observance-history milestones attached to May 17. Each observance keeps its own source and date details.
Verified history
Today in history →On this date in observance history
Selected observance milestones connected to this date, based on reviewed sources.
2022
Later action
National Women in Aerospace Day
Mayor Dana Ralph proclaimed May 20, 2022 as Women in Aerospace Day in Kent, providing later municipal recognition of the creator-led observance.
2013
Precursor
Randol Fawkes Labour Day
The existing first-Friday-in-June Labour Day public holiday was renamed Randol Fawkes Labour Day by Act No. 9 of 2013.
2007
First observance
International Child Helpline Day
CHI’s 2010 annual report and briefing material state that the first International Child Helpline Day was celebrated in 2007.
2007
First observance
World Telecommunication and Information Society Day
ITU event archives show 2007 as the first event listed under the combined World Telecommunication and Information Society Day name, after the 2006 merger decision.
2005
First observance
International Day against Homophobia, Transphobia and Biphobia (IDAHOBIT)
The current official history says the first International Day Against Homophobia was observed in 2005, and the annual date is May 17.
1989
Institutional decision
World No Tobacco Day
WHA42.19 records adoption at the twelfth plenary meeting on 17 May 1989.
1957
First observance
National Defense Transportation Day
Proclamation 3183 designated Friday, 17 May 1957, as National Defense Transportation Day.
Curated global anchors
See the collection →Major global guides on May 17
A reviewed starting point drawn from prominent global observances with strong institutional or organizer sources. Each observance keeps its own documented status and scope.
Source-backedFixed AnnualIn-depth guide
World Telecommunication and Information Society Day
A/RES/60/252
Reviewed depth
Other in-depth guides on May 17
Source-backedRule Based AnnualIn-depth guide
International AIDS Candlelight Memorial
The International AIDS Candlelight Memorial states that the memorial is held every third Sunday in May and has been observed since 1983 under coordination by GNP+.
Source-backedFixed AnnualIn-depth guide
International Child Helpline Day
Child Helpline International first-party reports identify 17 May as International Child Helpline Day, state that the first edition was celebrated in 2007, and show continuing network observ…
Source-backedFixed AnnualIn-depth guide
International Day against Homophobia, Transphobia and Biphobia (IDAHOBIT)
The IDAHOBIT campaign’s 2026 material identifies May 17 as the International Day against Homophobia, Transphobia and Biphobia and describes global participation around the date.
Source-backedFixed AnnualIn-depth guide
National Idaho Day
National Day Calendar lists its private National Idaho Day on May 17 within the 2017 National State Days series. The U.S. Senate separately records July 3, 1890 statehood, while Idaho educa…
Source-backedRule Based AnnualIn-depth guide
National Take Your Parents to the Playground Day
PDPlay says it established the observance in 2009 and that president John Ogden conceptualized it. Older PDPlay material used the Saturday before Easter weekend; current PDPlay material pro…
Source-backedFixed AnnualIn-depth guide
World NF Awareness Day
CTF verifies May 17 as World NF Awareness Day, distinguishes May 22 NF2-SWN awareness, and archives public use by 2013; the reviewed first-party sources do not establish a single founder or…
Explore the mix
All topics →Topics represented on May 17
7 observances
All observances on this date
Source-backedRule Based AnnualIn-depth guide
International AIDS Candlelight Memorial
The International AIDS Candlelight Memorial states that the memorial is held every third Sunday in May and has been observed since 1983 under coordination by GNP+.
Source-backedFixed AnnualIn-depth guide
International Child Helpline Day
Child Helpline International first-party reports identify 17 May as International Child Helpline Day, state that the first edition was celebrated in 2007, and show continuing network observ…
Source-backedFixed AnnualIn-depth guide
International Day against Homophobia, Transphobia and Biphobia (IDAHOBIT)
The IDAHOBIT campaign’s 2026 material identifies May 17 as the International Day against Homophobia, Transphobia and Biphobia and describes global participation around the date.
Source-backedFixed AnnualIn-depth guide
National Idaho Day
National Day Calendar lists its private National Idaho Day on May 17 within the 2017 National State Days series. The U.S. Senate separately records July 3, 1890 statehood, while Idaho educa…
Source-backedRule Based AnnualIn-depth guide
National Take Your Parents to the Playground Day
PDPlay says it established the observance in 2009 and that president John Ogden conceptualized it. Older PDPlay material used the Saturday before Easter weekend; current PDPlay material pro…
Source-backedFixed AnnualIn-depth guide
World NF Awareness Day
CTF verifies May 17 as World NF Awareness Day, distinguishes May 22 NF2-SWN awareness, and archives public use by 2013; the reviewed first-party sources do not establish a single founder or…
Source-backedFixed AnnualIn-depth guide
World Telecommunication and Information Society Day
A/RES/60/252
How dates are selected
This page combines fixed annual dates, reusable calendar rules and year-specific dates confirmed for 2026. Variable or historical dates are included only when they are clearly supported.
Read the methodology →