diff --git a/src/fs/open_file.rs b/src/fs/open_file.rs
index ce005dc..c4d8560 100644
--- a/src/fs/open_file.rs
+++ b/src/fs/open_file.rs
@@ -53,6 +53,10 @@ impl OpenFile {
         self.state.lock().await.1.flags
     }
 
+    pub async fn set_flags(&self, flags: OpenFlags) {
+        self.state.lock().await.1.flags = flags;
+    }
+
     pub async fn lock(&self) -> AsyncMutexGuard<'_, (Box<dyn FileOps>, FileCtx)> {
         self.state.lock().await
     }
diff --git a/src/process/fd_table/fcntl.rs b/src/process/fd_table/fcntl.rs
index f3d08b0..8353034 100644
--- a/src/process/fd_table/fcntl.rs
+++ b/src/process/fd_table/fcntl.rs
@@ -1,9 +1,9 @@
-use bitflags::Flags;
-use libkernel::error::{KernelError, Result};
-
 use super::Fd;
 use crate::process::fd_table::dup::dup_fd;
 use crate::{process::fd_table::FdFlags, sched::current::current_task_shared};
+use bitflags::Flags;
+use libkernel::error::{KernelError, Result};
+use libkernel::fs::OpenFlags;
 
 const F_DUPFD: u32 = 0; // Duplicate file descriptor.
 const F_GETFD: u32 = 1; // Get file descriptor flags.
@@ -54,7 +54,25 @@ pub async fn sys_fcntl(fd: Fd, op: u32, arg: usize) -> Result<usize> {
 
             Ok(open_fd.flags().await.bits() as _)
         }
-        F_SETFL => todo!(),
+        F_SETFL => {
+            let fl = OpenFlags::from_bits_retain(arg as _);
+            if fl.contains_unknown_bits() {
+                return Err(KernelError::InvalidValue);
+            }
+            let open_fd = {
+                let mut fds = task.fd_table.lock_save_irq();
+                let fd = fds
+                    .entries
+                    .get_mut(fd.as_raw() as usize)
+                    .and_then(|entry| entry.as_mut())
+                    .ok_or(KernelError::BadFd)?;
+
+                fd.file.clone()
+            };
+            // TODO: Ignore sync/dsync when implemented
+            open_fd.set_flags(fl).await;
+            Ok(0)
+        }
         _ => Err(KernelError::InvalidValue),
     }
 }