diff --git a/solutions/elixir/triangle/2/lib/triangle.ex b/solutions/elixir/triangle/2/lib/triangle.ex
new file mode 100644
index 0000000..5bb0761
--- /dev/null
+++ b/solutions/elixir/triangle/2/lib/triangle.ex
@@ -0,0 +1,19 @@
+defmodule Triangle do
+  @type kind :: :equilateral | :isosceles | :scalene
+
+  @doc """
+  Return the kind of triangle of a triangle with 'a', 'b' and 'c' as lengths.
+  """
+  @spec kind(number, number, number) :: {:ok, kind} | {:error, String.t()}
+  def kind(a, b, c) when a <= 0 or b <= 0 or c <= 0,
+    do: {:error, "all side lengths must be positive"}
+    
+  def kind(a, b, c) when a + b < c or b + c < a or c + a < b,
+    do: {:error, "side lengths violate triangle inequality"}
+    
+  def kind(a, a, a), do: {:ok, :equilateral}
+  def kind(a, a, _), do: {:ok, :isosceles}
+  def kind(a, _, a), do: {:ok, :isosceles}
+  def kind(_, a, a), do: {:ok, :isosceles}
+  def kind(_, _, _), do: {:ok, :scalene}
+end