diff --git a/vlib/json/cjson/cjson_wrapper.c.v b/vlib/json/cjson/cjson_wrapper.c.v
index 34bc9f4169..879900f1a9 100644
--- a/vlib/json/cjson/cjson_wrapper.c.v
+++ b/vlib/json/cjson/cjson_wrapper.c.v
@@ -12,6 +12,15 @@ module cjson
 #flag @VEXEROOT/thirdparty/cJSON/cJSON.o
 #include "cJSON.h"
 
+// As cJSON use `libm`, we need to link it.
+$if windows {
+	$if tinyc {
+		#flag @VEXEROOT/thirdparty/tcc/lib/openlibm.o
+	}
+} $else {
+	#flag -lm
+}
+
 @[flag]
 pub enum CJsonType {
 	t_false
diff --git a/vlib/json/json_primitives.c.v b/vlib/json/json_primitives.c.v
index 9a6c740da7..97fec6cd5d 100644
--- a/vlib/json/json_primitives.c.v
+++ b/vlib/json/json_primitives.c.v
@@ -8,6 +8,15 @@ module json
 #include "cJSON.h"
 #define js_get(object, key) cJSON_GetObjectItemCaseSensitive((object), (key))
 
+// As cJSON use `libm`, we need to link it.
+$if windows {
+	$if tinyc {
+		#flag @VEXEROOT/thirdparty/tcc/lib/openlibm.o
+	}
+} $else {
+	#flag -lm
+}
+
 pub struct C.cJSON {
 	valueint    int
 	valuedouble f64