diff --git a/library/std/src/sys/wasi/ext/fs.rs b/library/std/src/sys/wasi/ext/fs.rs
index a8da003d550ac..1dc7983f18831 100644
--- a/library/std/src/sys/wasi/ext/fs.rs
+++ b/library/std/src/sys/wasi/ext/fs.rs
@@ -397,6 +397,8 @@ pub trait MetadataExt {
     fn ino(&self) -> u64;
     /// Returns the `st_nlink` field of the internal `filestat_t`
     fn nlink(&self) -> u64;
+    /// Returns the `st_size` field of the internal `filestat_t`
+    fn size(&self) -> u64;
     /// Returns the `st_atim` field of the internal `filestat_t`
     fn atim(&self) -> u64;
     /// Returns the `st_mtim` field of the internal `filestat_t`
@@ -415,6 +417,9 @@ impl MetadataExt for fs::Metadata {
     fn nlink(&self) -> u64 {
         self.as_inner().as_wasi().nlink
     }
+    fn size(&self) -> u64 {
+        self.as_inner().as_wasi().size
+    }
     fn atim(&self) -> u64 {
         self.as_inner().as_wasi().atim
     }