diff --git a/include/ofi.h b/include/ofi.h
index 9661a7553d9..6239a6b1f3c 100644
--- a/include/ofi.h
+++ b/include/ofi.h
@@ -320,7 +320,7 @@ struct ofi_filter {
 
 extern struct ofi_filter prov_log_filter;
 extern struct fi_provider core_prov;
-extern const char *log_prefix;
+extern _Thread_local const char *log_prefix;
 
 void ofi_create_filter(struct ofi_filter *filter, const char *env_name);
 void ofi_free_filter(struct ofi_filter *filter);
diff --git a/src/common.c b/src/common.c
index 0d641ac74a1..4ae2d411afd 100644
--- a/src/common.c
+++ b/src/common.c
@@ -2429,4 +2429,4 @@ size_t ofi_vrb_speed(uint8_t speed, uint8_t width)
 }
 
 /* log_prefix is used by fi_log and by prov/util */
-const char *log_prefix = "";
+_Thread_local const char *log_prefix = "";