Remembrance Day (also known as Armistice Day) is on the 11th November.
It marks the day that WW1 ended at 11am, on the 11th day of the 11th month (in 1918).
A two minute silence is held (at 11am) to remember all those who have died as a result of war (not just WW1).
Many people choose to wear a poppy in November to show respect for the people who died fighting in WW1 and other wars that have followed.
The reason poppies are used to remember those who have given their lives in battle is because they are the flowers which grew on the battlefields after WW1 ended.
There are other coloured poppies too - purple, black and white.
Click here to find out more about what the different coloured poppies mean.
Will you wear a poppy on Remembrance Day?
If so, which colour will you wear?
You might like to watch this child-friendly story of the poppy: