diff --git a/src/Fable.Cli/CHANGELOG.md b/src/Fable.Cli/CHANGELOG.md
index db5040bdd..abc466a14 100644
--- a/src/Fable.Cli/CHANGELOG.md
+++ b/src/Fable.Cli/CHANGELOG.md
@@ -7,6 +7,10 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## Unreleased
 
+### Added
+
+* [JS/TS] Add support for `OrdinalIgnoreCase` overload for `String.EndsWith` (#3892) (by @goswinr)
+
 ### Changed
 
 * [Python] Remove `$` sign when reporting an error from `assert_equal` and `assert_not_equal` (#3878) (by @joprice)
diff --git a/src/Fable.Transforms/Replacements.fs b/src/Fable.Transforms/Replacements.fs
index efce42c56..f281afb38 100644
--- a/src/Fable.Transforms/Replacements.fs
+++ b/src/Fable.Transforms/Replacements.fs
@@ -1449,7 +1449,6 @@ let implementedStringFunctions =
         [|
             "Compare"
             "CompareTo"
-            "EndsWith"
             "Format"
             "IndexOfAny"
             "Insert"
@@ -1503,12 +1502,15 @@ let strings (com: ICompiler) (ctx: Context) r t (i: CallInfo) (thisArg: Expr opt
 
         let left = Helper.InstanceCall(c, "indexOf", Int32.Number, [ arg ])
         makeEqOp r left (makeIntConst 0) BinaryGreaterOrEqual |> Some
-    | "StartsWith", Some c, [ _str ] ->
-        let left = Helper.InstanceCall(c, "indexOf", Int32.Number, args)
-        makeEqOp r left (makeIntConst 0) BinaryEqual |> Some
+    | "StartsWith", Some c, [ _str ] -> Helper.InstanceCall(c, "startsWith", Boolean, args) |> Some
     | "StartsWith", Some c, [ _str; _comp ] ->
         Helper.LibCall(com, "String", "startsWith", t, args, i.SignatureArgTypes, thisArg = c, ?loc = r)
         |> Some
+    | "EndsWith", Some c, [ _str ] -> Helper.InstanceCall(c, "endsWith", Boolean, args) |> Some
+    | "EndsWith", Some c, [ _str; _comp ] ->
+        Helper.LibCall(com, "String", "endsWith", t, args, i.SignatureArgTypes, thisArg = c, ?loc = r)
+        |> Some
+
     | ReplaceName [ "ToUpper", "toLocaleUpperCase"
                     "ToUpperInvariant", "toUpperCase"
                     "ToLower", "toLocaleLowerCase"
diff --git a/src/fable-library-ts/CHANGELOG.md b/src/fable-library-ts/CHANGELOG.md
index c9f5ec329..e82a31c94 100644
--- a/src/fable-library-ts/CHANGELOG.md
+++ b/src/fable-library-ts/CHANGELOG.md
@@ -7,6 +7,10 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## Unreleased
 
+### Added
+
+* [JS/TS] Add support for `OrdinalIgnoreCase` overload for `String.EndsWith` (#3892) (by @goswinr)
+
 ### Fixed
 
 * [JS/TS] Fix escaping of `{` and `}` in FormattableString (#3890) (by @roboz0r)
diff --git a/src/fable-library-ts/String.ts b/src/fable-library-ts/String.ts
index 955cf0697..6b58e844b 100644
--- a/src/fable-library-ts/String.ts
+++ b/src/fable-library-ts/String.ts
@@ -64,12 +64,25 @@ export function compareTo(x: string, y: string) {
 }
 
 export function startsWith(str: string, pattern: string, ic: number) {
+  if (ic === StringComparison.Ordinal) { // to avoid substring allocation
+    return str.startsWith(pattern);
+  }
   if (str.length >= pattern.length) {
     return cmp(str.substr(0, pattern.length), pattern, ic) === 0;
   }
   return false;
 }
 
+export function endsWith(str: string, pattern: string, ic: number) {
+  if (ic === StringComparison.Ordinal) { // to avoid substring allocation
+    return str.endsWith(pattern);
+  }
+  if (str.length >= pattern.length) {
+    return cmp(str.substr(str.length - pattern.length, pattern.length), pattern, ic) === 0;
+  }
+  return false;
+}
+
 export function indexOfAny(str: string, anyOf: string[], ...args: number[]) {
   if (str == null || str === "") {
     return -1;
@@ -374,10 +387,6 @@ export function format(str: string | object, ...args: any[]) {
   });
 }
 
-export function endsWith(str: string, search: string) {
-  const idx = str.lastIndexOf(search);
-  return idx >= 0 && idx === str.length - search.length;
-}
 
 export function initialize(n: number, f: (i: number) => string) {
   if (n < 0) {
diff --git a/tests/Js/Main/StringTests.fs b/tests/Js/Main/StringTests.fs
index 31a63960c..bda0f73e7 100644
--- a/tests/Js/Main/StringTests.fs
+++ b/tests/Js/Main/StringTests.fs
@@ -815,23 +815,28 @@ let tests = testList "Strings" [
         "abcdbcebc".IndexOfAny([|'c';'b'|]) |> equal 1
 
     testCase "String.StartsWith works" <| fun () ->
-        let args = [("ab", true); ("cd", false); ("abcdx", false)]
+        let args = [("ab", true); ("bc", false); ("cd", false); ("abcdx", false); ("abcd", true)]
         for arg in args do
                 "abcd".StartsWith(fst arg)
                 |> equal (snd arg)
 
-    testCase "String.StartsWith with StringComparison works" <| fun () ->
-        let args = [("ab", true); ("cd", false); ("abcdx", false)]
+    testCase "String.StartsWith with OrdinalIgnoreCase works" <| fun () ->
+        let args = [("ab", true); ("AB", true); ("BC", false); ("cd", false); ("abcdx", false); ("abcd", true)]
         for arg in args do
                 "ABCD".StartsWith(fst arg, StringComparison.OrdinalIgnoreCase)
                 |> equal (snd arg)
 
-
     testCase "String.EndsWith works" <| fun () ->
-        let args = [("ab", false); ("cd", true); ("abcdx", false)]
+        let args = [("ab", false); ("cd", true);  ("bc", false); ("abcdx", false); ("abcd", true)]
         for arg in args do
                 "abcd".EndsWith(fst arg)
                 |> equal (snd arg)
+    
+    testCase "String.EndsWith with OrdinalIgnoreCase works" <| fun () ->
+        let args = [("ab", false); ("CD", true); ("cd", true); ("bc", false); ("xabcd", false); ("abcd", true)]
+        for arg in args do
+                "ABCD".EndsWith(fst arg, StringComparison.OrdinalIgnoreCase)
+                |> equal (snd arg)                
 
     testCase "String.Trim works" <| fun () ->
         "   abc   ".Trim()