Children's Day

World Day Against Child Labour, and its related observances:
Children's Day (Haiti)

Women Veterans Day

Women Veterans Recognition Day (United States)

Russia Day

Russia Day (Russia)

Loving Day

Loving Day (United States)

Public holidays in Nigeria

June 12 Commemoration (Lagos State)

Helsinki Day

Helsinki Day (Finland)

Dia dos Namorados

Dia dos Namorados (Brazil)

June 12 (Eastern Orthodox liturgics)

Christian feast day:
June 12 (Eastern Orthodox liturgics)

Ternan

Christian feast day:
Ternan

Pope Leo III

Christian feast day:
Pope Leo III

Onuphrius

Christian feast day:
Onuphrius

John of Sahagún

Christian feast day:
John of Sahagún

Gaspare Bertoni

Christian feast day:
Gaspar Bertoni

First Council of Nicaea

Christian feast day:
First Ecumenical Council (Lutheran)

Saint Eskil

Christian feast day:
Eskil