diff --git a/c/libraries.c b/c/libraries.c
index 65d9811..2940631 100644
--- a/c/libraries.c
+++ b/c/libraries.c
@@ -58,6 +58,7 @@ static struct builtin_procedure builtin_procedures[] = {
 
     { "string?", fl_stringp, SRFI_13 | R7RS_BASE | UP_2019 },
     { "string-reverse", fl_string_reverse, SRFI_13 | UP_2019 },
+    { "string-split", builtin_string_split, UP_2019 },
     { "substring", fl_string_sub, R7RS_BASE | UP_2019 },
 
     { "environment-stack", builtin_environment_stack, UP_2019 },
diff --git a/c/scheme.h b/c/scheme.h
index 3d5ccc1..2f76223 100644
--- a/c/scheme.h
+++ b/c/scheme.h
@@ -1004,6 +1004,7 @@ value_t builtin_set_environment_variable(value_t *args, uint32_t nargs);
 
 value_t fl_stringp(value_t *args, uint32_t nargs);
 value_t fl_string_reverse(value_t *args, uint32_t nargs);
+value_t builtin_string_split(value_t *args, uint32_t nargs);
 value_t fl_string_sub(value_t *args, uint32_t nargs);
 
 // util.c
diff --git a/c/string.c b/c/string.c
index 7cb8763..7a3e80e 100644
--- a/c/string.c
+++ b/c/string.c
@@ -162,16 +162,16 @@ value_t fl_string(value_t *args, uint32_t nargs)
     return outp;
 }
 
-value_t fl_string_split(value_t *args, uint32_t nargs)
+value_t builtin_string_split(value_t *args, uint32_t nargs)
 {
     char *s;
     char *delim;
     size_t len, dlen, ssz, tokend, tokstart, i, junk;
     value_t first, c, last;
 
-    argcount("string.split", nargs, 2);
-    s = tostring(args[0], "string.split");
-    delim = tostring(args[1], "string.split");
+    argcount("string-split", nargs, 2);
+    s = tostring(args[0], "string-split");
+    delim = tostring(args[1], "string-split");
     len = cv_len((struct cvalue *)ptr(args[0]));
     dlen = cv_len((struct cvalue *)ptr(args[1]));
     tokend = tokstart = i = 0;
@@ -497,7 +497,6 @@ static struct builtinspec stringfunc_info[] = {
     { "string?", fl_stringp },
     { "string.count", fl_string_count },
     { "string.width", fl_string_width },
-    { "string.split", fl_string_split },
     { "string.sub", fl_string_sub },
     { "string.find", fl_string_find },
     { "string.char", fl_string_char },