Thor, the Norse god of thunder, is frequently depicted with his magic hammer, Mjolnir. From the hammer amulets that the Vikings used to wear to the hammer carried by the Marvel hero of comics and movies, Mjolnir is an instantly recognizable symbol for Thor himself.
Thor got his hammer, Mjolnir, in Norse mythology from the dwarves Brokkr and Sindri (sometimes called Eitri) when Loki made a bet with the dwarves to determine the better blacksmith. Mjolnir was a remarkable weapon that could kill giants, bless marriages, and restore the dead to life.
This article will explain how Thor got his hammer in Norse mythology, as well as discuss the Marvel movies and how they depict Thor and his hammer.
Also see Why Is Thor the God of Thunder? to learn more.
Who Gave Thor His Hammer?
The story of the creation of Thor’s hammer can be found in Snorri’s Prose Edda, one of the two main sources of Norse mythology. 
In the myth, the dwarf Brokkr gives Thor his hammer because of a bet that Loki makes. Loki owes Thor a favor and convinces the dwarves to smith beautiful objects for the gods, including Mjolnir.
The story begins with Loki, the trickster god, who cuts the hair off of the goddess Sif, Thor’s wife. Thor, enraged on his wife’s behalf, threatens to beat Loki. He only escapes unharmed by promising to visit the dwarves, who can smith new hair for Sif out of gold.
Loki meets with dwarves called Ivaldi’s sons, who agree to craft Sif hair of gold. They also build a fast ship that can be folded into one’s pocket and a deadly spear.
But rather than return to Asgard, Loki sees an opportunity to get more gifts for the gods. He approaches two dwarves called Brokkr and Sindri, also called Eitri, and presents them with a challenge.
He bets that they cannot craft three items as beautiful and precious as the ones Ivaldi’s sons made. Should Brokkr and Sindri win the bet, Loki promises them his head.
Brokkr and Sindri accept and start crafting a living boar made out of gold. A fly (whom scholars presume to be a shapeshifting Loki in disguise) bites the dwarves while they work, but they continue anyway. Next, they make a golden ring that produces eight identical rings every nine days.
While the dwarves are smithing a war hammer, the fly bites Brokkr on the eye. He cannot see what he is doing at the forge, and he creates a hammer of unparalleled strength — but the handle is noticeably too short.
Sindri says that the fly nearly ruined the hammer.
Loki and Brokkr go to Asgard to present the gods with their gifts. Odin received the spear, Gungnir, and the magic ring, Draupnir, while Frey received the ship and the boar. Thor received Sif’s golden hair and the hammer.
The gods decide that Mjolnir is the best of all the gifts, and Brokkr wins the bet with Loki. Loki avoids beheading, but he does have his mouth sewn shut for his tricky words.
Also see How Old Is Thor? to learn more.
The Marvel Movies Version
In the Marvel movies, Mjolnir is a gift to Thor from his father, Odin. An alien race of dwarves renowned for their smithing skills reside on the star Nidavellir. Per Odin’s request, they forge the hammer in the heart of the dying star.
In a nod to mythology, the leader of the dwarves is named Eitri, the alternate name for Sindri.
What Is Thor’s Hammer Made Out Of?
Norse mythology does not detail how Mjolnir works, what it looks like, or what it is made of. Snorri spends more time describing the abilities of the hammer than he does about its makeup.
According to myth, Thor’s hammer is made of iron or a combination of iron and another metal. The only indication of Mjolnir’s material composition comes from a single line in the Prose Edda that reads, “Sindri laid iron in the hearth.” 
Strangely, Mjolnir is iron and not some magical metal.
In a contest with Draupnir, the ring that can produce infinite gold rings, and Skidbladnir, the wooden ship that can collapse into Frey’s pocket, Mjollnir wins. The gods choose this iron hammer with a too-short handle over flawless gold.
The Marvel movies make Mjolnir a little more exciting than plain iron. In the movies, the dwarves make Thor’s hammer out of a special metal called Uru, which they forge in the core of a collapsing star.
Also see How Did Thor Lose His Eye? to learn more.
Do Marvel Movies Depict Thor’s Powers Accurately?
Thor’s powers in Norse mythology are not very clearly defined. He is associated with lightning and thunder, but he rarely summons storms. He is incredibly strong, with and without his hammer. With the help of Mjollnir, he can defeat most enemies, and hallow places, objects, and unions.
The Marvel movies do not depict Thor’s powers accurately. In the movies, Thor summons lightning far more often than he does in myth, he can fly with his hammer, and Mjolnir’s role as a holy object is ignored.
The Marvel movies do not depict Mjolnir’s ability to hallow objects.
Thor’s hammer in mythology is both an instrument of destruction and consecration. It blesses marriages, and in one story, it can restore Thor’s pet goats to life.
Mjolnir in Marvel is not much of a holy object but is primarily a weapon. However, some scenes hint at its other uses from myth.
When Tony Stark and Bruce Banner create the Vision in Avengers: Age of Ultron, Thor uses Mjolnir to generate a lightning strike that seemingly brings Vision to life. This appears to be less about Mjolnir’s holy abilities and more about using electricity to bestow life.
In the Marvel movies, only someone deemed “worthy” can lift Mjolnir.
Worthy individuals include Thor, Odin, Vision, Carol Danvers, and Steve Rogers. Perhaps the worthiness test is an echo of Mjolnir’s ability to bless, a way for the hammer (and Thor) to show favor to certain individuals.
The Avengers movies repeat that Thor is the god of thunder, not of hammers. Instead of making Thor just an accomplished warrior with a magic hammer, the movies set him apart from the other superheroes by giving him lightning powers.
Though the Marvel movies take liberties with mythology when it comes to Thor, the god of thunder and his iconic hammer remain an inseparable pair.