diff --git a/test/typescript-tests/testTypes.ts b/test/typescript-tests/testTypes.ts
index 9a6d066481..a95ff8ab3a 100644
--- a/test/typescript-tests/testTypes.ts
+++ b/test/typescript-tests/testTypes.ts
@@ -1822,6 +1822,14 @@ Units examples
     expectTypeOf(math.unit(math.fraction(5, 2), 'cm')).toExtend<Unit>()
     expectTypeOf(math.unit(math.complex(5, 0), 'cm')).toExtend<Unit>()
 
+    // Test unit function with MathNumericType and a valueless Unit
+    const cm = math.unit('cm')
+    expectTypeOf(math.unit(5, cm)).toExtend<Unit>()
+    expectTypeOf(math.unit(math.bignumber(5), cm)).toExtend<Unit>()
+    expectTypeOf(math.unit(math.fraction(5, 2), cm)).toExtend<Unit>()
+    expectTypeOf(math.unit(math.complex(5, 0), cm)).toExtend<Unit>()
+    expectTypeOf(math.chain(5).unit(cm)).toExtend<MathJsChain<Unit>>()
+
     // Test unit function with just MathNumericType (optional unit parameter)
     expectTypeOf(math.unit(5)).toExtend<Unit>()
     expectTypeOf(math.unit(math.bignumber(5))).toExtend<Unit>()
diff --git a/types/index.d.ts b/types/index.d.ts
index d37ff59f22..b22c65da53 100644
--- a/types/index.d.ts
+++ b/types/index.d.ts
@@ -928,7 +928,7 @@ export interface MathJsInstance extends MathJsFactory {
    * @param unit The unit to be created
    * @returns The created unit
    */
-  unit(value: MathNumericType, unit?: string): Unit
+  unit(value: MathNumericType, unit?: string | Unit): Unit
   unit(value: MathCollection): Unit[]
 
   /*************************************************************************
@@ -5103,7 +5103,10 @@ export interface MathJsChain<TValue> {
    * @param unit The unit to be created
    */
   unit(this: MathJsChain<string>, unit?: string): MathJsChain<Unit>
-  unit(this: MathJsChain<MathNumericType>, unit?: string): MathJsChain<Unit>
+  unit(
+    this: MathJsChain<MathNumericType>,
+    unit?: string | Unit
+  ): MathJsChain<Unit>
   unit(this: MathJsChain<MathCollection>): MathJsChain<Unit[]>
 
   /*************************************************************************