diff --git a/lab05/kvtree/kvtree.ml b/lab05/kvtree/kvtree.ml
new file mode 100644
index 0000000..4b048ca
--- /dev/null
+++ b/lab05/kvtree/kvtree.ml
@@ -0,0 +1,140 @@
+module type OrderedType = sig
+  type t
+  val compare : t -> t -> int
+end
+
+module type S = sig
+  type k
+  type ('k, 'v) t
+  exception Not_found
+
+  val empty : (k, 'v) t
+  val is_empty : (k, 'v) t -> bool
+  val insert : k -> 'v -> (k, 'v) t -> (k, 'v) t
+  val find_opt : k -> (k, 'v) t -> 'v option
+  val delete : k -> (k, 'v) t -> (k, 'v) t
+  val of_list : (k * 'v) list -> (k, 'v) t
+  val size : (k, 'v) t -> int
+  val find : k -> (k, 'v) t -> 'v
+  val to_list : (k, 'v) t -> (k * 'v) list
+  val to_string : ((k * 'v) -> string) -> (k, 'v) t -> string
+end
+
+module Make(Ord: OrderedType) = struct
+  (** [k] is the key of a key-value pair *)
+  type k = Ord.t
+
+  (** [t] is a key-value tree where each N has a key, value, left and right *)
+  type ('k, 'v) t = L | N of k * 'v * (k, 'v) t * (k, 'v) t;;
+
+  (** [Not_found] exception if a given key cannot be found in the tree *)
+  exception Not_found;;
+
+  (** empty tree *)
+  let empty = L;;
+
+  (** [is_empty t] takes a kvtree [t] and checks if it is empty or not *)
+  let is_empty t = t = L;;
+
+  (** [insert k v t] takes a comparator [], key [k], value [v],
+    * and a kvtree [t] to insert the key and value [k, v] into the tree [t]. *)
+  let rec insert k v t =
+    match t with
+    | L -> N (k, v, L, L)
+    | N (k', v', l, r) when Ord.compare k k' < 0 ->
+      N (k', v', insert  k v l, r)
+    | N (k', v', l, r) when Ord.compare k k' > 0 ->
+      N (k', v', l, insert  k v r)
+    | _ -> t;;
+
+  (** [find_opt k t] takes a key [k] and a kvtree [t] and returns
+    * an Optional value found from the given key [k]. *)
+  let rec find_opt k t =
+    match t with
+    | L -> None
+    | N (k', _, l, _) when Ord.compare k k' < 0 ->
+      find_opt  k l
+    | N (k', _, _, r) when Ord.compare k k' > 0 ->
+      find_opt  k r
+    | N (_, v, _, _) -> Some v;;
+
+  (** [largest t] finds the largest key in a given kvtree [t]
+    * and retursn the key value pair [k, v] *)
+  let rec largest t =
+    match t with
+    | L -> failwith "largest: empty tree"
+    | N (k, v, _, L) -> (k, v)
+    | N (_, _, _, r) -> largest r;;
+
+  (** [smallest t] finds the smallest key in a given kvtree [t]
+    * and retursn the key value pair [k, v] *)
+  let rec smallest t =
+    match t with
+    | L -> failwith "smallest: empty tree"
+    | N (k, v, L, _) -> (k, v)
+    | N (_, _, l, _) -> smallest l;;
+
+  (** [delete k t] takes a key [k] and deletes it from a given
+    * kvtree [t]. *)
+  let rec delete k t =
+    match t with
+    | L -> L
+    | N (k', v, l, r) when Ord.compare k k' < 0 ->
+      N (k', v, delete  k l, r)
+    | N (k', v, l, r) when Ord.compare k k' > 0 ->
+      N (k', v, l, delete  k r)
+    | N (_, _, l, L) -> l
+    | N (_, _, L, r) -> r
+    | N (_, _, l, r) ->
+      let (ks, vs) = largest l in
+      N (ks, vs, delete  ks l, r);;
+
+  (** [of_list l] takes a list of pairs [l] and creates a
+    * kvtree in the order specefied by the comparator [] to compare
+    * keys *)
+  let of_list  l =
+    List.fold_left (fun acc (k, v) -> insert  k v acc) L l;;
+
+  (** [size t] takes a kvtree [t] and returns the size of the tree
+    * i.e. number of Ns *)
+  let rec size t =
+    match t with
+    | L -> 0
+    | N (_, _, l, r) ->
+      1 + size l + size r;;
+
+  (** [find k t] takes a key [k] and a kvtree [t] and returns
+    * a value found from the given key [k]. *)
+  let rec find k t =
+    match t with
+    | L -> raise Not_found
+    | N (k', _, l, _) when Ord.compare k k' < 0 ->
+      find k l
+    | N (k', _, _, r) when Ord.compare k k' > 0 ->
+      find k r
+    | N (_, v, _, _) -> v;;
+
+  (** [to_list t] takes a key-value tree [t] and returns
+    * a list representation of the key-value pairs *)
+  let to_list t =
+    let rec aux acc t =
+      match t with
+      | L -> acc
+      | N (k, v, l, r) ->
+        aux ((k, v) :: (aux acc r)) l
+    in
+    aux [] t;;
+
+  (** [to_string f t] takes a function [f] to "convert" a
+    * key-value pair to a string, and applies that to all
+    * key-value pairs in a given tree [t]. *)
+  let to_string f t =
+    let rec aux acc t =
+      match t with
+      | L -> "#"
+      | N (k, v, l, r) ->
+        Printf.sprintf "^(%s, %s, %s)" (f (k, v)) (aux acc l) (aux acc r)
+    in
+    aux "" t;;
+
+end
diff --git a/lab05/kvtree/kvtree.mli b/lab05/kvtree/kvtree.mli
new file mode 100644
index 0000000..503e6cd
--- /dev/null
+++ b/lab05/kvtree/kvtree.mli
@@ -0,0 +1,23 @@
+module type OrderedType = sig
+  type t
+  val compare : t -> t -> int
+end
+
+module type S = sig
+  type k
+  type ('k, 'v) t
+  exception Not_found
+
+  val empty : (k, 'v) t
+  val is_empty : (k, 'v) t -> bool
+  val insert : k -> 'v -> (k, 'v) t -> (k, 'v) t
+  val find_opt : k -> (k, 'v) t -> 'v option
+  val delete : k -> (k, 'v) t -> (k, 'v) t
+  val of_list : (k * 'v) list -> (k, 'v) t
+  val size : (k, 'v) t -> int
+  val find : k -> (k, 'v) t -> 'v
+  val to_list : (k, 'v) t -> (k * 'v) list
+  val to_string : ((k * 'v) -> string) -> (k, 'v) t -> string
+end
+
+module Make(Ord: OrderedType) : S with type k = Ord.t
diff --git a/lab05/kvtree/tests.ml b/lab05/kvtree/tests.ml
new file mode 100644
index 0000000..eed9c6d
--- /dev/null
+++ b/lab05/kvtree/tests.ml
@@ -0,0 +1,39 @@
+(* This is a minimal test file.  Your program must pass these tests in order
+   to get any credit for your work.
+   In utop:
+   #directory "_build";;
+   #load "kvtree.cmo";;
+   #use "tests.ml";;
+   run ();;
+ *)
+module M = Kvtree.Make(Int);;
+
+let t = M.of_list [(3, "three"); (2, "two"); (7, "seven"); (6, "six"); (8, "eight")]
+let l = [(2, "two"); (3, "three"); (6, "six"); (7, "seven"); (8, "eight")]
+let s =
+  "^(3, three, ^(2, two, #, #), ^(7, seven, ^(6, six, #, #), ^(8, eight, #, #)))"
+
+let t2 = M.of_list [(3, 'a')]
+let s2 = "^(3, a, #, #)"
+
+let t3 = M.insert 2 'b' t2
+let s3 = "^(3, a, ^(2, b, #, #), #)"
+
+let t4 = M.of_list [(3, "3"); (7, "7"); (5, "5"); (6, "6"); (8, "8"); (9, "9")]
+let s4 = "^(3, 3, #, ^(7, 7, ^(5, 5, #, ^(6, 6, #, #)), ^(8, 8, #, ^(9, 9, #, #))))"
+let t5 = M.delete 7 t4
+let s5a = "^(3, 3, #, ^(6, 6, ^(5, 5, #, #), ^(8, 8, #, ^(9, 9, #, #))))"
+let s5b = "^(3, 3, #, ^(8, 8, ^(5, 5, #, ^(6, 6, #, #)), ^(9, 9, #, #)))"
+
+let run () =
+  assert (M.size t = 5);
+  assert (M.find 7 t = "seven");
+  assert (M.find_opt 7 t = Some "seven");
+  assert (M.to_list t = l);
+  assert (M.to_string (fun (k, v) -> Printf.sprintf "%d, %s" k v) t = s);
+  assert (M.to_string (fun (k, v) -> Printf.sprintf "%d, %c" k v) t2 = s2);
+  assert (M.to_string (fun (k, v) -> Printf.sprintf "%d, %c" k v) t3 = s3);
+  assert (M.to_string (fun (k, v) -> Printf.sprintf "%d, %s" k v) t4 = s4);
+  assert (
+    let s = M.to_string (fun (k, v) -> Printf.sprintf "%d, %s" k v) t5 in
+    s = s5a || s = s5b)