The family-owned company with headquarters in Billund, Denmark, announced the move on Tuesday as it reported that net profits dropped by 3% to 3.4bn Danish kroner (£420m).
Revenue also fell by 5% to 14.9bn Danish kroner (£1.8bn), its results for the first half of this year showed.
Lego, which employs 19,000 people across the world, including 900 in the UK, said the job cuts were part of a major overhaul to "reset the company".
It said those affected by the cuts would be offered redundancy packages and support as they moved on.
Chairman Jorgen Vig Knudstorp said: "We are disappointed by the decline in revenue in our established markets, and we have taken steps to address this."
He said the firm needed to reduce its costs and the company's "increasingly complex" business model needed simplifying.
"We are very sorry to make changes which may interfere with the lives of many of our colleagues," he said.
"Our colleagues put so much passion into their work every day and we are deeply grateful for that.
Unfortunately, it is essential for us to make these tough decisions."