diff --git a/solutions/count_vowels.py b/solutions/count_vowels.py
new file mode 100644
index 000000000..61c19e7da
--- /dev/null
+++ b/solutions/count_vowels.py
@@ -0,0 +1,46 @@
+#!/usr/bin/env python3
+# -*- coding: utf-8 -*-
+"""
+A module for counting the number of vowels in a given string.
+
+Created on 29 Dec 2024
+@author: Daniel Oluwaluyi
+"""
+
+
+def count_vowels(input_string: str) -> int:
+    """
+    Count the number of vowels in the provided string.
+
+    This function takes a string as input and counts the occurrences
+    of vowels (a, e, i, o, u), including both lowercase and uppercase letters.
+
+    Args:
+        input_string (str): The input string to process.
+
+    Returns:
+        int: The count of vowels in the input string.
+
+    Raises:
+        AssertionError: If the input is not a string.
+
+    Doctests:
+        >>> count_vowels("hello")
+        2
+        >>> count_vowels("HELLO")
+        2
+        >>> count_vowels("12345!@#$%^&*()")
+        0
+        >>> count_vowels("aeiouAEIOU")
+        10
+        >>> count_vowels("")
+        0
+    """
+    # Defensive assertion to ensure the input is a string
+    assert isinstance(input_string, str), "Input must be a string"
+
+    # Define a set of vowels for quick lookup
+    vowels = set("aeiouAEIOU")
+
+    # Count and return the number of vowels in the string
+    return sum(1 for char in input_string if char in vowels)
diff --git a/solutions/tests/test_count_vowels.py b/solutions/tests/test_count_vowels.py
new file mode 100644
index 000000000..51b5d0507
--- /dev/null
+++ b/solutions/tests/test_count_vowels.py
@@ -0,0 +1,53 @@
+#!/usr/bin/env python3
+# -*- coding: utf-8 -*-
+"""
+A module for testing the count_vowels function.
+
+Created on 29 Dec 2024
+@author: Daniel Oluwaluyi
+"""
+
+import unittest
+
+from solutions.count_vowels import count_vowels
+
+
+class TestCountVowels(unittest.TestCase):
+    """A class for testing the count_vowels function."""
+
+    def test_empty_string(self):
+        """Test the count_vowels function with an empty string."""
+        self.assertEqual(count_vowels(""), 0)
+
+    def test_no_vowels(self):
+        """Test the count_vowels function with a string containing no vowels."""
+        self.assertEqual(count_vowels("bcdfghjklmnpqrstvwxyz"), 0)
+
+    def test_all_vowels(self):
+        """Test the count_vowels function with a string containing all vowels."""
+        self.assertEqual(count_vowels("aeiouAEIOU"), 10)
+
+    def test_mixed_string(self):
+        """Test the count_vowels function with a string containing vowels and consonants."""
+        self.assertEqual(count_vowels("Hello, World!"), 3)
+
+    def test_numeric_and_special_characters(self):
+        """Test the count_vowels function with a string containing numbers and special characters."""
+        self.assertEqual(count_vowels("12345!@#$%^&*()"), 0)
+
+    def test_vowels_in_words(self):
+        """Test the count_vowels function with a string containing multiple words."""
+        self.assertEqual(count_vowels("Python programming is fun!"), 6)
+
+    def test_string_with_whitespace(self):
+        """Test the count_vowels function with a string containing leading and trailing whitespace."""
+        self.assertEqual(count_vowels("  aeiou  "), 5)
+
+    def test_non_string_input(self):
+        """Test the count_vowels function with a non-string input."""
+        with self.assertRaises(AssertionError):
+            count_vowels(12345)
+
+
+if __name__ == "__main__":
+    unittest.main()