In the Summer of 1940, young Luxembourgers openly showed their opposition to the German policy. The first to decide upon organised Resistance were the Luxembourg boy scouts.

Among students from different high schools, groups were formed and decided to put up resistance to the German occupation:

At the end of 1940 and in early 1941, other local movements also became active. These went in contact with one another and decided to work together and unite forces by merging into larger groups.

At the end of 1941, three larger groups were active: LVL, LPL (two groups in Luxembourg, one in Brussels), and LRL. The Pi-men decided not to join the other groups for security reasons. The only political party that continued its activities as Resistance was the underground communist party.

Some groups were dismantled by the Gestapo, and numerous Resistance fighters were sent to concentration camps. In February 1944, 23 Resistance fighters were shot near the concentration camp of Hinzert.

In March 1944, the surviving Resistance groups gathered in one national movement: The Union of Luxembourg Resistance Movements, which tried to take power after the liberation.

The Luxembourg Resistance was largely unarmed. Until the Summer of 1942, they were mainly organising counter propaganda to reinforce the patriotism of the population. In October 1941, they convinced a large majority to fill in a census formula with ‘Luxembourg’ for language, race, and nationality. Whereas the German occupiers had asked them to write ‘German’. The census was cancelled.

When compulsory military service was introduced, Resistance groups encouraged people to go on strike. 21 men were arrested at random, condemned to death and shot.

The Resistance printed and distributed flyers and newspapers, also producing photographs with Grand Duchess Charlotte. They collected explosives and weapons for self-defence. These were the main activities before they started to create networks to help young people to leave the country to avoid serving in the German army. They helped French prisoners of war and allied aircrew to find their way back through escape lines. Some 2,000 young people went into hiding in Luxembourg and had to be fed.

More and more people gathered economic and military information that was sent to the allied secret services in London. The information gathered by young Luxembourgers on the site of Peenemünde lead to the Allies eventually bombing the facility in 1943.