diff --git a/Libraries/LibRegex/RegexOptimizer.cpp b/Libraries/LibRegex/RegexOptimizer.cpp
index fdb95e73bd2..4a4738cad7c 100644
--- a/Libraries/LibRegex/RegexOptimizer.cpp
+++ b/Libraries/LibRegex/RegexOptimizer.cpp
@@ -1372,34 +1372,48 @@ void Optimizer::append_alternation(ByteCode& target, Span<ByteCode> alternatives
             auto opcode_bytes = alternative_bytes.slice(state.instruction_position, opcode.size());
 
             switch (opcode.opcode_id()) {
-            case OpCodeId::Jump:
-                incoming_jump_edges.ensure(static_cast<OpCode_Jump const&>(opcode).offset() + state.instruction_position).append({ opcode_bytes });
-                has_any_backwards_jump |= static_cast<OpCode_Jump const&>(opcode).offset() < 0;
+            case OpCodeId::Jump: {
+                auto const& cast_opcode = static_cast<OpCode_Jump const&>(opcode);
+                incoming_jump_edges.ensure(cast_opcode.offset() + cast_opcode.size() + state.instruction_position).append({ opcode_bytes });
+                has_any_backwards_jump |= cast_opcode.offset() < 0;
                 break;
-            case OpCodeId::JumpNonEmpty:
-                incoming_jump_edges.ensure(static_cast<OpCode_JumpNonEmpty const&>(opcode).offset() + state.instruction_position).append({ opcode_bytes });
-                has_any_backwards_jump |= static_cast<OpCode_JumpNonEmpty const&>(opcode).offset() < 0;
+            }
+            case OpCodeId::JumpNonEmpty: {
+                auto const& cast_opcode = static_cast<OpCode_JumpNonEmpty const&>(opcode);
+                incoming_jump_edges.ensure(cast_opcode.offset() + cast_opcode.size() + state.instruction_position).append({ opcode_bytes });
+                has_any_backwards_jump |= cast_opcode.offset() < 0;
                 break;
-            case OpCodeId::ForkJump:
-                incoming_jump_edges.ensure(static_cast<OpCode_ForkJump const&>(opcode).offset() + state.instruction_position).append({ opcode_bytes });
-                has_any_backwards_jump |= static_cast<OpCode_ForkJump const&>(opcode).offset() < 0;
+            }
+            case OpCodeId::ForkJump: {
+                auto const& cast_opcode = static_cast<OpCode_ForkJump const&>(opcode);
+                incoming_jump_edges.ensure(cast_opcode.offset() + cast_opcode.size() + state.instruction_position).append({ opcode_bytes });
+                has_any_backwards_jump |= cast_opcode.offset() < 0;
                 break;
-            case OpCodeId::ForkStay:
-                incoming_jump_edges.ensure(static_cast<OpCode_ForkStay const&>(opcode).offset() + state.instruction_position).append({ opcode_bytes });
-                has_any_backwards_jump |= static_cast<OpCode_ForkStay const&>(opcode).offset() < 0;
+            }
+            case OpCodeId::ForkStay: {
+                auto const& cast_opcode = static_cast<OpCode_ForkStay const&>(opcode);
+                incoming_jump_edges.ensure(cast_opcode.offset() + cast_opcode.size() + state.instruction_position).append({ opcode_bytes });
+                has_any_backwards_jump |= cast_opcode.offset() < 0;
                 break;
-            case OpCodeId::ForkReplaceJump:
-                incoming_jump_edges.ensure(static_cast<OpCode_ForkReplaceJump const&>(opcode).offset() + state.instruction_position).append({ opcode_bytes });
-                has_any_backwards_jump |= static_cast<OpCode_ForkReplaceJump const&>(opcode).offset() < 0;
+            }
+            case OpCodeId::ForkReplaceJump: {
+                auto const& cast_opcode = static_cast<OpCode_ForkReplaceJump const&>(opcode);
+                incoming_jump_edges.ensure(cast_opcode.offset() + cast_opcode.size() + state.instruction_position).append({ opcode_bytes });
+                has_any_backwards_jump |= cast_opcode.offset() < 0;
                 break;
-            case OpCodeId::ForkReplaceStay:
-                incoming_jump_edges.ensure(static_cast<OpCode_ForkReplaceStay const&>(opcode).offset() + state.instruction_position).append({ opcode_bytes });
-                has_any_backwards_jump |= static_cast<OpCode_ForkReplaceStay const&>(opcode).offset() < 0;
+            }
+            case OpCodeId::ForkReplaceStay: {
+                auto const& cast_opcode = static_cast<OpCode_ForkReplaceStay const&>(opcode);
+                incoming_jump_edges.ensure(cast_opcode.offset() + cast_opcode.size() + state.instruction_position).append({ opcode_bytes });
+                has_any_backwards_jump |= cast_opcode.offset() < 0;
                 break;
-            case OpCodeId::Repeat:
-                incoming_jump_edges.ensure(state.instruction_position - static_cast<OpCode_Repeat const&>(opcode).offset()).append({ opcode_bytes });
+            }
+            case OpCodeId::Repeat: {
+                auto const& cast_opcode = static_cast<OpCode_Repeat const&>(opcode);
+                incoming_jump_edges.ensure(state.instruction_position - cast_opcode.offset()).append({ opcode_bytes });
                 has_any_backwards_jump = true;
                 break;
+            }
             default:
                 break;
             }
diff --git a/Tests/LibRegex/TestRegex.cpp b/Tests/LibRegex/TestRegex.cpp
index bf8b19a39f3..50bd974f349 100644
--- a/Tests/LibRegex/TestRegex.cpp
+++ b/Tests/LibRegex/TestRegex.cpp
@@ -1367,3 +1367,15 @@ TEST_CASE(zero_width_backreference)
         EXPECT_EQ(result.capture_group_matches.first()[0].view.to_byte_string(), ""sv);
     }
 }
+
+TEST_CASE(account_for_opcode_size_calculating_incoming_jump_edges)
+{
+    {
+        // The optimizer should not optimize the initial ForkStay for these alternatives as they are jumped to from different locations.
+        Regex<ECMA262> re(".*a|.*b", ECMAScriptFlags::Global);
+        auto result = re.match("aa"sv);
+        EXPECT_EQ(result.success, true);
+        EXPECT_EQ(result.matches.size(), 1u);
+        EXPECT_EQ(result.matches.first().view.to_byte_string(), "aa"sv);
+    }
+}