diff --git a/src/Collections/List.hpp b/src/Collections/List.hpp
index c2a7362..d84ed4a 100644
--- a/src/Collections/List.hpp
+++ b/src/Collections/List.hpp
@@ -48,6 +48,16 @@ namespace Arbutils::Collections {
             return std::find(_vector.begin(), _vector.end(), value) != _vector.end();
         }
 
+        /// Find the index of the first occurrence of a value in the list, return -1 if none is found.
+        /// \param value The value we want the index for.
+        /// \return The index of the first occurrence of the value in the list, or -1 if none is found.
+        inline size_t IndexOf(ValueT value) const {
+            auto it = std::find(_vector.begin(), _vector.end(), value);
+            if (it == _vector.end())
+                return -1;
+            return std::distance(_vector.begin(), it);
+        }
+
         inline void Append(ValueT value) { _vector.push_back(value); }
 
         inline void Insert(size_t index, ValueT value) { _vector.insert(index, value); }
@@ -59,9 +69,7 @@ namespace Arbutils::Collections {
         inline void Resize(size_t size) { _vector.resize(size); }
         inline void Resize(size_t size, ValueT defaultValue) { _vector.resize(size, defaultValue); }
 
-        inline void Remove(size_t index){
-            _vector.erase(_vector.begin() + index);
-        }
+        inline void Remove(size_t index) { _vector.erase(_vector.begin() + index); }
 
         iterator begin() { return _vector.begin(); }
         const_iterator begin() const { return _vector.begin(); }
diff --git a/tests/ListTests.cpp b/tests/ListTests.cpp
index ab2ccb2..4ea928f 100644
--- a/tests/ListTests.cpp
+++ b/tests/ListTests.cpp
@@ -60,6 +60,15 @@ TEST_CASE("Create list of bools, assign to it", "[Utilities]") {
     CHECK(ls[1]);
 }
 
+TEST_CASE("Test IndexOf", "[Utilities]") {
+    auto ls = List<int>({5, 200, 1500, -500, 5, 300, -500});
+    CHECK(ls.IndexOf(5) == 0);
+    CHECK(ls.IndexOf(1500) == 2);
+    CHECK(ls.IndexOf(300) == 5);
+    CHECK(ls.IndexOf(684) == -1);
+}
+
+
 
 
 #endif
\ No newline at end of file