diff --git a/core/sys/linux/bits.odin b/core/sys/linux/bits.odin
index 213d6c26f..59383638d 100644
--- a/core/sys/linux/bits.odin
+++ b/core/sys/linux/bits.odin
@@ -2269,3 +2269,9 @@ Swap_Flags_Bits :: enum {
 	PREFER  = log2(0x8000),
 	DISCARD = log2(0x10000),
 }
+
+Eventfd_Flags_Bits :: enum {
+	SEMAPHORE,
+	CLOEXEC  = auto_cast Open_Flags_Bits.CLOEXEC,
+	NONBLOCK = auto_cast Open_Flags_Bits.NONBLOCK,
+}
diff --git a/core/sys/linux/sys.odin b/core/sys/linux/sys.odin
index faeda6f43..b10759595 100644
--- a/core/sys/linux/sys.odin
+++ b/core/sys/linux/sys.odin
@@ -3001,7 +3001,10 @@ timerfd_create :: proc "contextless" (clock_id: Clock_Id, flags: Open_Flags) ->
 	return errno_unwrap2(ret, Fd)
 }
 
-// TODO(flysand): eventfd
+eventfd :: proc "contextless" (initval: u32, flags: Eventfd_Flags) -> (Fd, Errno) {
+	ret := syscall(SYS_eventfd2, initval, transmute(i32)flags)
+	return errno_unwrap2(ret, Fd)
+}
 
 // TODO(flysand): fallocate
 
diff --git a/core/sys/linux/types.odin b/core/sys/linux/types.odin
index 0910f11ec..de4417beb 100644
--- a/core/sys/linux/types.odin
+++ b/core/sys/linux/types.odin
@@ -1748,3 +1748,5 @@ Mount_Flags :: bit_set[Mount_Flags_Bits; uint]
 Umount2_Flags :: bit_set[Umount2_Flags_Bits; u32]
 
 Swap_Flags :: bit_set[Swap_Flags_Bits; u32]
+
+Eventfd_Flags :: bit_set[Eventfd_Flags_Bits; i32]