diff --git a/src/main.cpp b/src/main.cpp
index ab37de95cdd0b96ab24ce52d6aa74a1a8bcf8673..2dc500b1bbfc056145bc45ba8bd6814df42ee525 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -700,7 +700,7 @@ int main(int argc, char **argv) {
 
                 ZigTarget *non_null_target = target ? target : &native;
 
-                Buf *test_exe_name = buf_sprintf("./test%s", target_exe_file_ext(non_null_target));
+                Buf *test_exe_name = buf_sprintf("." OS_SEP "test%s", target_exe_file_ext(non_null_target));
 
                 for (size_t i = 0; i < test_exec_args.length; i += 1) {
                     if (test_exec_args.items[i] == nullptr) {
diff --git a/src/os.hpp b/src/os.hpp
index 0d4e8d3dbaf995eaab6d9a1676874672addc37f7..44dd361d17ecae33c80c851b14f11fc2b50fa0ea 100644
--- a/src/os.hpp
+++ b/src/os.hpp
@@ -85,11 +85,13 @@ bool os_is_sep(uint8_t c);
 #define ZIG_PRI_u64 "I64u"
 #define ZIG_PRI_llu "I64u"
 #define ZIG_PRI_x64 "I64x"
+#define OS_SEP "\\"
 #else
 #define ZIG_PRI_usize "zu"
 #define ZIG_PRI_u64 PRIu64
 #define ZIG_PRI_llu "llu"
 #define ZIG_PRI_x64 PRIx64
+#define OS_SEP "/"
 #endif
 
 #endif