diff --git a/pkgs/development/compilers/emscripten/default.nix b/pkgs/development/compilers/emscripten/default.nix
index c31f109f8908..a91316046706 100644
--- a/pkgs/development/compilers/emscripten/default.nix
+++ b/pkgs/development/compilers/emscripten/default.nix
@@ -8,7 +8,7 @@
 
 stdenv.mkDerivation rec {
   pname = "emscripten";
-  version = "3.1.51";
+  version = "3.1.55";
 
   llvmEnv = symlinkJoin {
     name = "emscripten-llvm-${version}";
@@ -19,7 +19,7 @@ stdenv.mkDerivation rec {
     name = "emscripten-node-modules-${version}";
     inherit pname version src;
 
-    npmDepsHash = "sha256-N7WbxzKvW6FljY6g3R//9RdNiezhXGEvKPbOSJgdA0g=";
+    npmDepsHash = "sha256-7tZEZ7NN1jJBHa9G5sRz/ZpWJvgnTJj4i5EvQMsGQH4=";
 
     dontBuild = true;
 
@@ -32,7 +32,7 @@ stdenv.mkDerivation rec {
   src = fetchFromGitHub {
     owner = "emscripten-core";
     repo = "emscripten";
-    hash = "sha256-oXecS6B0u8YLeoybjxLwx5INGj/Kp/8GA6s3A1S0y4k=";
+    hash = "sha256-3SqbkXI8xn4Zj3bDLCegxslYH5m/PkF6n/pPfm5z5VA=";
     rev = version;
   };
 
@@ -42,7 +42,7 @@ stdenv.mkDerivation rec {
   patches = [
     (substituteAll {
       src = ./0001-emulate-clang-sysroot-include-logic.patch;
-      resourceDir = "${llvmEnv}/lib/clang/17/";
+      resourceDir = "${llvmEnv}/lib/clang/18/";
     })
   ];
 
@@ -51,8 +51,8 @@ stdenv.mkDerivation rec {
 
     patchShebangs .
 
-    # emscripten 3.1.50 requires LLVM tip-of-tree instead of LLVM 17
-    sed -i -e "s/EXPECTED_LLVM_VERSION = 18/EXPECTED_LLVM_VERSION = 17.0/g" tools/shared.py
+    # emscripten 3.1.55 requires LLVM tip-of-tree instead of LLVM 18
+    sed -i -e "s/EXPECTED_LLVM_VERSION = 19/EXPECTED_LLVM_VERSION = 18/g" tools/shared.py
 
     # fixes cmake support
     sed -i -e "s/print \('emcc (Emscript.*\)/sys.stderr.write(\1); sys.stderr.flush()/g" emcc.py
diff --git a/pkgs/top-level/all-packages.nix b/pkgs/top-level/all-packages.nix
index c99d2166fc88..475b9095191a 100644
--- a/pkgs/top-level/all-packages.nix
+++ b/pkgs/top-level/all-packages.nix
@@ -7698,7 +7698,7 @@ with pkgs;
   easeprobe = callPackage ../tools/misc/easeprobe { };
 
   emscripten = callPackage ../development/compilers/emscripten {
-    llvmPackages = llvmPackages_17;
+    llvmPackages = llvmPackages_18;
   };
 
   emscriptenPackages = recurseIntoAttrs (callPackage ./emscripten-packages.nix { });