diff --git a/src/function.js b/src/function.js
index 23c6436..fd9263f 100644
--- a/src/function.js
+++ b/src/function.js
@@ -1,6 +1,6 @@
 import { curry, curryN } from './curry.js'
 import { dispatch } from './fantasy-land.js'
-import { concat as iconcat, iter } from './list.js'
+import { concat as iconcat, isIterable, iter } from './list.js'
 
 /** @import { Fn, Morphism, InferredMorphism, Predicate } from './types.js' */
 
@@ -18,8 +18,13 @@ export const id = x => x
 export const pipe = (...fns) => x => fns.reduce((v, f) => f(v), x)
 
 export const concat = dispatch(['fantasy-land/concat', 'concat'],
-  (b, a) => iconcat(iter(a), iter(b))
-)
+  (b, a) => {
+    if (isIterable(a) || isIterable(b)) {
+      return iconcat(iter(a), iter(b))
+    } else {
+      return a.concat(b)
+    }
+  })
 
 export const compose = dispatch(['fantasy-land/compose', 'compose'],
   /**
diff --git a/src/type.js b/src/type.js
index 660e4ff..113b074 100644
--- a/src/type.js
+++ b/src/type.js
@@ -25,4 +25,5 @@ export const is = curry(
 export const isFn = x => type(x) === 'function'
 
 export const isArray = Array.isArray
+export const isIterable = x => x != null ? typeof x[Symbol.iterator] === 'function' : false