diff --git a/CHANGELOG.md b/CHANGELOG.md
index 1ce1376..0a9c1e5 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -4,6 +4,10 @@ For breaking changes, check [here](#breaking-changes).
 
 [Babashka CLI](https://github.com/babashka/cli): turn Clojure functions into CLIs!
 
+## Unreleased
+
+- [#116](https://github.com/babashka/cli/issues/116): Undeprecate `:collect` option to support custom transformation of arguments to collections
+
 ## v0.8.62 (2024-12-22)
 
 - Fix [#109](https://github.com/babashka/cli/issues/109): allow options to start with a number
diff --git a/README.md b/README.md
index e6eb807..3c32d53 100644
--- a/README.md
+++ b/README.md
@@ -208,6 +208,19 @@ Arguments that start with `--no-` arg parsed as negative flags (since 0.7.51):
 ;;=> {:colors false}
 ```
 
+### Custom collection handling
+
+Usually the above will suffice, but for custom transformation to a collection, you can use `:collect`.
+Here's an example of parsing out `,` separated multi-arg-values:
+
+``` clojure
+(cli/parse-opts ["--foo" "a,b" "--foo=c,d,e" "--foo" "f"]
+                {:collect {:foo (fn [coll arg-value]
+                                  (into (or coll [])
+                                        (str/split arg-value #",")))}})
+;; => {:foo ["a" "b" "c" "d" "e" "f"]}
+```
+
 ### Auto-coercion
 
 Since `v0.3.35` babashka CLI auto-coerces values that have no explicit coercion
@@ -430,6 +443,7 @@ An explanation of each key:
 - `:require`: `true` make this opt required.
 - `:validate`: a function used to validate the value of this opt (as described
   in the [Validate](#validate) section).
+- `:collect`: for custom collection/transformation of argument values
 
 ## Help
 
diff --git a/src/babashka/cli.cljc b/src/babashka/cli.cljc
index 3d7c26b..6e30652 100644
--- a/src/babashka/cli.cljc
+++ b/src/babashka/cli.cljc
@@ -282,6 +282,7 @@
   * `:exec-args` - a map of default args. Will be overridden by args specified in `args`.
   * `:no-keyword-opts` - `true`. Support only `--foo`-style opts (i.e. `:foo` will not work).
   * `:args->opts` - consume unparsed commands and args as options
+  * `:collect` - a map of collection fns. See [custom collection handling](https://github.com/babashka/cli#custom-collection-handling).
 
   Examples:
 
diff --git a/test/babashka/cli_test.cljc b/test/babashka/cli_test.cljc
index 2b0a119..59700f7 100644
--- a/test/babashka/cli_test.cljc
+++ b/test/babashka/cli_test.cljc
@@ -172,7 +172,10 @@
                                                  :coerce {:verbose []}}))))
 
 (deftest spec-test
-  (let [spec {:from {:ref "<format>"
+  (let [multi-arg-val-collect (fn [coll arg-value]
+                                  (into (or coll [])
+                                        (str/split arg-value #":")))
+        spec {:from {:ref "<format>"
                      :desc "The input format. <format> can be edn, json or transit."
                      :coerce :keyword
                      :alias :i
@@ -189,18 +192,23 @@
               :paths {:desc "Paths of files to transform."
                       :coerce []
                       :default ["src" "test"]
-                      :default-desc "src test"}}]
+                      :default-desc "src test"}
+              :multi {:desc "Custom multi-arg-val test."
+                      :alias :m
+                      :collect multi-arg-val-collect}}]
     (is (= (str/trim "
   -i, --from   <format> edn      The input format. <format> can be edn, json or transit.
   -o, --to     <format> json     The output format. <format> can be edn, json or transit.
       --paths           src test Paths of files to transform.
-  -p, --pretty                   Pretty-print output.")
+  -p, --pretty                   Pretty-print output.
+  -m, --multi                    Custom multi-arg-val test.")
            (str/trim (cli/format-opts {:spec spec
-                                       :order [:from :to :paths :pretty]}))))
+                                       :order [:from :to :paths :pretty :multi]}))))
     (is (= {:coerce {:from :keyword,
                      :to :keyword, :paths []},
-            :alias {:i :from, :o :to, :p :pretty},
-            :exec-args {:from :edn, :to :json, :paths ["src" "test"]}}
+            :alias {:i :from, :o :to, :p :pretty :m :multi},
+            :exec-args {:from :edn, :to :json, :paths ["src" "test"]}
+            :collect {:multi multi-arg-val-collect}}
            (cli/spec->opts spec nil)))
     (is (= (str/trim "
   -p, --pretty false    Pretty-print output.
@@ -213,6 +221,11 @@
                                       :coerce []
                                       :default ["src" "test"]
                                       :default-desc "src test"}]]}))))
+    (is (submap?
+          {:opts {:from :edn :to :json :paths ["src" "test"]
+                  :multi ["a" "b" "c" "d" "e" "f" "g" "h"]}}
+          (cli/parse-args ["--multi" "a:b" "--multi" "c:d:e" "--multi" "f" "--multi" "g" "h"]
+                          {:spec spec})))
     (is (submap?
          {:opts {:from :edn, :to :json, :paths ["src" "test"]}}
          (cli/parse-args [] {:spec spec})))
@@ -222,6 +235,7 @@
          #:deps{:root "the-root"}
          (cli/parse-opts ["--deps/root" "the-root"]
                          {:spec [[:deps/root {:desc "The root"}]]})))
+
     (testing "exec-args wins over spec"
       (is (= 2 (:foo (cli/parse-opts [] {:spec {:foo {:default 1}}
                                          :exec-args {:foo 2}}))))