diff --git a/.changeset/poor-fishes-pretend.md b/.changeset/poor-fishes-pretend.md
new file mode 100644
index 0000000000..5bee4bc37b
--- /dev/null
+++ b/.changeset/poor-fishes-pretend.md
@@ -0,0 +1,5 @@
+---
+"@latticexyz/world": patch
+---
+
+Added system signatures to the `FunctionSignatures` table, so they can be used to generate system ABIs and decode system calls made via the world.
diff --git a/packages/world-modules/gas-report.json b/packages/world-modules/gas-report.json
index 5c555d87b2..8bfcd3de5e 100644
--- a/packages/world-modules/gas-report.json
+++ b/packages/world-modules/gas-report.json
@@ -303,7 +303,7 @@
     "file": "test/UniqueEntityModule.t.sol",
     "test": "testInstall",
     "name": "install unique entity module",
-    "gasUsed": 710507
+    "gasUsed": 715495
   },
   {
     "file": "test/UniqueEntityModule.t.sol",
@@ -315,7 +315,7 @@
     "file": "test/UniqueEntityModule.t.sol",
     "test": "testInstallRoot",
     "name": "installRoot unique entity module",
-    "gasUsed": 680976
+    "gasUsed": 685964
   },
   {
     "file": "test/UniqueEntityModule.t.sol",
diff --git a/packages/world/gas-report.json b/packages/world/gas-report.json
index 1eb0de70d3..04c9ccb0b4 100644
--- a/packages/world/gas-report.json
+++ b/packages/world/gas-report.json
@@ -105,7 +105,7 @@
     "file": "test/World.t.sol",
     "test": "testRegisterFunctionSelector",
     "name": "Register a function selector",
-    "gasUsed": 111621
+    "gasUsed": 116605
   },
   {
     "file": "test/World.t.sol",
diff --git a/packages/world/src/modules/init/implementations/WorldRegistrationSystem.sol b/packages/world/src/modules/init/implementations/WorldRegistrationSystem.sol
index e5fd723544..691697b0e4 100644
--- a/packages/world/src/modules/init/implementations/WorldRegistrationSystem.sol
+++ b/packages/world/src/modules/init/implementations/WorldRegistrationSystem.sol
@@ -202,8 +202,8 @@ contract WorldRegistrationSystem is System, IWorldErrors, LimitedCallContext {
 
     // Compute global function selector
     string memory namespaceString = WorldResourceIdLib.toTrimmedString(systemId.getNamespace());
-    bytes memory worldFunctionSignature = abi.encodePacked(namespaceString, "__", systemFunctionSignature);
-    worldFunctionSelector = bytes4(keccak256(worldFunctionSignature));
+    string memory worldFunctionSignature = string.concat(namespaceString, "__", systemFunctionSignature);
+    worldFunctionSelector = bytes4(keccak256(bytes(worldFunctionSignature)));
 
     // Require the function selector to be globally unique
     ResourceId existingSystemId = FunctionSelectors._getSystemId(worldFunctionSelector);
@@ -214,8 +214,9 @@ contract WorldRegistrationSystem is System, IWorldErrors, LimitedCallContext {
     bytes4 systemFunctionSelector = bytes4(keccak256(bytes(systemFunctionSignature)));
     FunctionSelectors._set(worldFunctionSelector, systemId, systemFunctionSelector);
 
-    // Register the function signature for offchain use
-    FunctionSignatures._set(worldFunctionSelector, string(worldFunctionSignature));
+    // Register the function signatures for offchain use
+    FunctionSignatures._set(systemFunctionSelector, systemFunctionSignature);
+    FunctionSignatures._set(worldFunctionSelector, worldFunctionSignature);
   }
 
   /**