diff --git a/tests/Conformance.test.cpp b/tests/Conformance.test.cpp
index c1b790b9..e4e0a662 100644
--- a/tests/Conformance.test.cpp
+++ b/tests/Conformance.test.cpp
@@ -64,7 +64,12 @@ static int lua_vector(lua_State* L)
     double y = luaL_checknumber(L, 2);
     double z = luaL_checknumber(L, 3);
 
+#if LUA_VECTOR_SIZE == 4
+    double w = luaL_optnumber(L, 4, 0.0);
+    lua_pushvector(L, float(x), float(y), float(z), float(w));
+#else
     lua_pushvector(L, float(x), float(y), float(z));
+#endif
     return 1;
 }
 
@@ -366,11 +371,17 @@ TEST_CASE("Pack")
 
 TEST_CASE("Vector")
 {
+    ScopedFastFlag sff{"LuauIfElseExpressionBaseSupport", true};
+
     runConformance("vector.lua", [](lua_State* L) {
         lua_pushcfunction(L, lua_vector);
         lua_setglobal(L, "vector");
 
+#if LUA_VECTOR_SIZE == 4
+        lua_pushvector(L, 0.0f, 0.0f, 0.0f, 0.0f);
+#else
         lua_pushvector(L, 0.0f, 0.0f, 0.0f);
+#endif
         luaL_newmetatable(L, "vector");
 
         lua_pushstring(L, "__index");
diff --git a/tests/conformance/vector.lua b/tests/conformance/vector.lua
index 620f646a..7d18bda3 100644
--- a/tests/conformance/vector.lua
+++ b/tests/conformance/vector.lua
@@ -1,6 +1,9 @@
 -- This file is part of the Luau programming language and is licensed under MIT License; see LICENSE.txt for details
 print('testing vectors')
 
+-- detect vector size
+local vector_size = if pcall(function() return vector(0, 0, 0).w end) then 4 else 3
+
 -- equality
 assert(vector(1, 2, 3) == vector(1, 2, 3))
 assert(vector(0, 1, 2) == vector(-0, 1, 2))
@@ -13,8 +16,14 @@ assert(not rawequal(vector(1, 2, 3), vector(1, 2, 4)))
 
 -- type & tostring
 assert(type(vector(1, 2, 3)) == "vector")
-assert(tostring(vector(1, 2, 3)) == "1, 2, 3")
-assert(tostring(vector(-1, 2, 0.5)) == "-1, 2, 0.5")
+
+if vector_size == 4 then
+	assert(tostring(vector(1, 2, 3, 4)) == "1, 2, 3, 4")
+	assert(tostring(vector(-1, 2, 0.5, 0)) == "-1, 2, 0.5, 0")
+else
+	assert(tostring(vector(1, 2, 3)) == "1, 2, 3")
+	assert(tostring(vector(-1, 2, 0.5)) == "-1, 2, 0.5")
+end
 
 local t = {}
 
@@ -42,12 +51,19 @@ assert(8 * vector(8, 16, 24) == vector(64, 128, 192));
 assert(vector(1, 2, 4) * '8' == vector(8, 16, 32));
 assert('8' * vector(8, 16, 24) == vector(64, 128, 192));
 
-assert(vector(1, 2, 4) / vector(8, 16, 24) == vector(1/8, 2/16, 4/24));
+if vector_size == 4 then
+	assert(vector(1, 2, 4, 8) / vector(8, 16, 24, 32) == vector(1/8, 2/16, 4/24, 8/32));
+	assert(8 / vector(8, 16, 24, 32) == vector(1, 1/2, 1/3, 1/4));
+	assert('8' / vector(8, 16, 24, 32) == vector(1, 1/2, 1/3, 1/4));
+else
+	assert(vector(1, 2, 4) / vector(8, 16, 24, 1) == vector(1/8, 2/16, 4/24));
+	assert(8 / vector(8, 16, 24) == vector(1, 1/2, 1/3));
+	assert('8' / vector(8, 16, 24) == vector(1, 1/2, 1/3));
+end
+
 assert(vector(1, 2, 4) / 8 == vector(1/8, 1/4, 1/2));
 assert(vector(1, 2, 4) / (1 / val) == vector(1/8, 2/8, 4/8));
-assert(8 / vector(8, 16, 24) == vector(1, 1/2, 1/3));
 assert(vector(1, 2, 4) / '8' == vector(1/8, 1/4, 1/2));
-assert('8' / vector(8, 16, 24) == vector(1, 1/2, 1/3));
 
 assert(-vector(1, 2, 4) == vector(-1, -2, -4));
 
@@ -71,4 +87,9 @@ assert(pcall(function() local t = {} rawset(t, vector(0/0, 2, 3), 1) end) == fal
 -- make sure we cover both builtin and C impl
 assert(vector(1, 2, 4) == vector("1", "2", "4"))
 
+-- additional checks for 4-component vectors
+if vector_size == 4 then
+	assert(vector(1, 2, 3, 4).w == 4)
+end
+
 return 'OK'