diff --git a/lib/libc/aarch64/string/Makefile.inc b/lib/libc/aarch64/string/Makefile.inc
--- a/lib/libc/aarch64/string/Makefile.inc
+++ b/lib/libc/aarch64/string/Makefile.inc
@@ -15,11 +15,13 @@
 	strchrnul \
 	strcmp \
 	strcpy \
-	strlen \
 	strncmp \
 	strnlen \
 	strrchr
 
+MDSRCS+= \
+	 strlen.S
+
 #
 # Add the above functions. Generate an asm file that includes the needed
 # Arm Optimized Routines file defining the function name to the libc name.
diff --git a/lib/libc/aarch64/string/strlen.S b/lib/libc/aarch64/string/strlen.S
new file mode 100644
--- /dev/null
+++ b/lib/libc/aarch64/string/strlen.S
@@ -0,0 +1,68 @@
+/*-
+ * Copyright (c) 2024 Getz Mikalsen
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+*/
+
+#include <machine/asm.h>
+
+	.text
+
+ENTRY(strlen)
+	bic	x10,x0,#0xf		// alignment
+	and	x9,x0,#0xf
+	ldr	q0,[x10]
+	cmeq	v0.16b,v0.16b,#0
+	shrn	v0.8b,v0.8h,#4
+	cbz	x9,.Laligned		// dont handle unaligned for prealigned
+	fmov	x1,d0
+	lsl	x2,x0,#2		// get the byte offset
+	lsr	x1,x1,x2		// shift by offset index
+	cbz	x1,.Lloop
+	rbit	x1,x1
+	clz	x0,x1
+	lsr	x0,x0,#2
+	ret
+
+	/*
+	 * If a string is already aligned we can skip a few cycles by handling
+	 * it as a special case.
+	 */
+
+.Laligned:
+	fmov	x1,d0
+	cbnz	x1,.Lfix
+
+	.p2align 4
+.Lloop:
+	ldr	q1,[x10,#16]
+	ldr	q2,[x10,#32]!
+	uminp	v0.16b,v1.16b,v2.16b	// Find smallest byte in buffer
+	uminp	v0.16b,v0.16b,v0.16b
+	cmeq	v0.8b,v0.8b,#0		// 0xFF if 0 in any buffer
+
+	fmov	x1,d0			// GPR move for loop check
+	cbz	x1,.Lloop
+
+	cmeq	v0.16b,v1.16b,#0	// Check if it matched in buf 1
+	sub	x0,x10,x0
+	cbnz	w1,1f			// If matched jump and find offset
+	cmeq	v0.16b,v2.16b,#0	// Check where match in buf 2
+	add	x0,x0,#16
+
+1:
+	shrn	v0.8b,v0.8h,#4		// Find offset of match
+	fmov	x1,d0
+	sub	x0,x0,#16
+	rbit	x1,x1			// reverse bits as NEON has no ctz
+	clz	x3,x1
+	lsr	x3,x3,#2		// get offset index
+	add	x0,x0,x3
+	ret
+
+.Lfix:
+	rbit	x1,x1
+	clz	x3,x1
+	lsr	x0,x3,#2
+	ret
+END(strlen)