diff --git a/unix/syscall_bsd.go b/unix/syscall_bsd.go
index 6f328e3a5..a00c3e545 100644
--- a/unix/syscall_bsd.go
+++ b/unix/syscall_bsd.go
@@ -316,7 +316,7 @@ func GetsockoptString(fd, level, opt int) (string, error) {
 	if err != nil {
 		return "", err
 	}
-	return string(buf[:vallen-1]), nil
+	return ByteSliceToString(buf[:vallen]), nil
 }
 
 //sys	recvfrom(fd int, p []byte, flags int, from *RawSockaddrAny, fromlen *_Socklen) (n int, err error)
diff --git a/unix/syscall_linux.go b/unix/syscall_linux.go
index 9b636ca07..0f85e29e6 100644
--- a/unix/syscall_linux.go
+++ b/unix/syscall_linux.go
@@ -1310,7 +1310,7 @@ func GetsockoptString(fd, level, opt int) (string, error) {
 			return "", err
 		}
 	}
-	return string(buf[:vallen-1]), nil
+	return ByteSliceToString(buf[:vallen]), nil
 }
 
 func GetsockoptTpacketStats(fd, level, opt int) (*TpacketStats, error) {
diff --git a/unix/syscall_solaris.go b/unix/syscall_solaris.go
index 60c8142d4..21974af06 100644
--- a/unix/syscall_solaris.go
+++ b/unix/syscall_solaris.go
@@ -158,7 +158,7 @@ func GetsockoptString(fd, level, opt int) (string, error) {
 	if err != nil {
 		return "", err
 	}
-	return string(buf[:vallen-1]), nil
+	return ByteSliceToString(buf[:vallen]), nil
 }
 
 const ImplementsGetwd = true
diff --git a/unix/syscall_zos_s390x.go b/unix/syscall_zos_s390x.go
index d99d05f1b..b473038c6 100644
--- a/unix/syscall_zos_s390x.go
+++ b/unix/syscall_zos_s390x.go
@@ -1104,7 +1104,7 @@ func GetsockoptString(fd, level, opt int) (string, error) {
 		return "", err
 	}
 
-	return string(buf[:vallen-1]), nil
+	return ByteSliceToString(buf[:vallen]), nil
 }
 
 func Recvmsg(fd int, p, oob []byte, flags int) (n, oobn int, recvflags int, from Sockaddr, err error) {