diff --git a/doc/lua_api.md b/doc/lua_api.md
index e82b075fb..b4ef79088 100644
--- a/doc/lua_api.md
+++ b/doc/lua_api.md
@@ -8892,7 +8892,7 @@ For `core.get_perlin_map()`, the actual seed used is the noiseparams seed
 plus the world seed, to create world-specific noise.
 
 Format of `size` is `{x=dimx, y=dimy, z=dimz}`. The `z` component is omitted
-for 2D noise, and it must be must be larger than 1 for 3D noise (otherwise
+for 2D noise, and it must be larger than 1 for 3D noise (otherwise
 `nil` is returned).
 
 For each of the functions with an optional `buffer` parameter: If `buffer` is