diff --git a/editor/CMakeLists.txt b/editor/CMakeLists.txt
index 69f31d6..311fdfd 100644
--- a/editor/CMakeLists.txt
+++ b/editor/CMakeLists.txt
@@ -2542,4 +2542,13 @@ target_link_libraries(step406_test PRIVATE
     tree_sitter_javascript tree_sitter_typescript
     tree_sitter_java tree_sitter_rust tree_sitter_go)
 
+add_executable(step407_test tests/step407_test.cpp)
+target_include_directories(step407_test PRIVATE src)
+target_link_libraries(step407_test PRIVATE
+    nlohmann_json::nlohmann_json
+    unofficial::tree-sitter::tree-sitter
+    tree_sitter_python tree_sitter_cpp tree_sitter_elisp
+    tree_sitter_javascript tree_sitter_typescript
+    tree_sitter_java tree_sitter_rust tree_sitter_go)
+
 # Step 12: Dear ImGui shell scaffolding created (main.cpp exists but not built due to dependencies)
diff --git a/editor/src/Pipeline.h b/editor/src/Pipeline.h
index 13a8138..fe0e4fc 100644
--- a/editor/src/Pipeline.h
+++ b/editor/src/Pipeline.h
@@ -122,6 +122,10 @@ public:
             auto pr = FSharpParser::parseFSharpWithDiagnostics(source);
             diags = std::move(pr.diagnostics);
             return std::move(pr.module);
+        } else if (language == "vbnet" || language == "vb" || language == "vb.net") {
+            auto pr = VBNetParser::parseVBNetWithDiagnostics(source);
+            diags = std::move(pr.diagnostics);
+            return std::move(pr.module);
         } else if (language == "c") {
             auto pr = CParser::parseCWithDiagnostics(source);
             diags = std::move(pr.diagnostics);
diff --git a/editor/src/ast/Parser.h b/editor/src/ast/Parser.h
index ce87ff8..b0ffcee 100644
--- a/editor/src/ast/Parser.h
+++ b/editor/src/ast/Parser.h
@@ -165,6 +165,7 @@ private:
 #include "ast/KotlinParser.h"
 #include "ast/CSharpParser.h"
 #include "ast/FSharpParser.h"
+#include "ast/VBNetParser.h"
 #include "ast/CParser.h"
 #include "ast/WatParser.h"
 #include "ast/CommonLispParser.h"
diff --git a/editor/src/ast/VBNetParser.h b/editor/src/ast/VBNetParser.h
new file mode 100644
index 0000000..437ed6e
--- /dev/null
+++ b/editor/src/ast/VBNetParser.h
@@ -0,0 +1,184 @@
+#pragma once
+
+#include "ASTNode.h"
+#include "Module.h"
+#include "Function.h"
+#include "Variable.h"
+#include "Statement.h"
+#include "ClassDeclaration.h"
+#include "EnumNamespaceNodes.h"
+#include "../ast/Parser.h"
+
+#include <string>
+#include <sstream>
+#include <cctype>
+
+class VBNetParser {
+public:
+    static std::unique_ptr<Module> parseVBNet(const std::string& source) {
+        auto module = std::make_unique<Module>();
+        module->id = IdGenerator::next("mod");
+        module->name = "parsed_vbnet_module";
+        module->targetLanguage = "vbnet";
+        parseTopLevel(source, module.get());
+        return module;
+    }
+
+    static ParseResult parseVBNetWithDiagnostics(const std::string& source) {
+        ParseResult result;
+        result.module = parseVBNet(source);
+        return result;
+    }
+
+private:
+    static void parseTopLevel(const std::string& source, Module* module) {
+        std::istringstream stream(source);
+        std::string line;
+
+        while (std::getline(stream, line)) {
+            std::string trimmed = trim(line);
+            if (trimmed.empty()) continue;
+            if (startsWithCaseInsensitive(trimmed, "'")) continue;
+
+            if (startsWithCaseInsensitive(trimmed, "Class ")) {
+                auto* cls = new ClassDeclaration();
+                cls->id = IdGenerator::next("cls");
+                cls->name = extractNameAfterKeyword(trimmed, "Class ");
+                module->addChild("classes", cls);
+                continue;
+            }
+
+            if (startsWithCaseInsensitive(trimmed, "Interface ")) {
+                auto* iface = new InterfaceDeclaration();
+                iface->id = IdGenerator::next("iface");
+                iface->name = extractNameAfterKeyword(trimmed, "Interface ");
+                module->addChild("interfaces", iface);
+                continue;
+            }
+
+            if (startsWithCaseInsensitive(trimmed, "Module ")) {
+                auto* ns = new NamespaceDeclaration();
+                ns->id = IdGenerator::next("ns");
+                ns->name = extractNameAfterKeyword(trimmed, "Module ");
+                module->addChild("statements", ns);
+                continue;
+            }
+
+            if (containsCaseInsensitive(trimmed, "Sub ") &&
+                !startsWithCaseInsensitive(trimmed, "End Sub")) {
+                auto* fn = new Function();
+                fn->id = IdGenerator::next("fn");
+                fn->name = extractMethodName(trimmed, "Sub ");
+                module->addChild("functions", fn);
+                continue;
+            }
+
+            if (containsCaseInsensitive(trimmed, "Function ") &&
+                !startsWithCaseInsensitive(trimmed, "End Function")) {
+                auto* fn = new Function();
+                fn->id = IdGenerator::next("fn");
+                fn->name = extractMethodName(trimmed, "Function ");
+                module->addChild("functions", fn);
+                continue;
+            }
+
+            if (startsWithCaseInsensitive(trimmed, "Dim ")) {
+                auto* var = new Variable();
+                var->id = IdGenerator::next("var");
+                var->name = extractDimName(trimmed);
+                module->addChild("variables", var);
+                continue;
+            }
+
+            if (startsWithCaseInsensitive(trimmed, "If ") &&
+                containsCaseInsensitive(trimmed, " Then")) {
+                auto* ifs = new IfStatement();
+                ifs->id = IdGenerator::next("if");
+                module->addChild("statements", ifs);
+                continue;
+            }
+
+            if (startsWithCaseInsensitive(trimmed, "For Each ") &&
+                containsCaseInsensitive(trimmed, " In ")) {
+                auto* loop = new ForLoop();
+                loop->id = IdGenerator::next("for");
+                loop->iteratorName = extractForEachIterator(trimmed);
+                module->addChild("statements", loop);
+                continue;
+            }
+        }
+    }
+
+    static std::string extractForEachIterator(const std::string& line) {
+        std::string lower = toLower(line);
+        size_t start = lower.find("for each ");
+        if (start == std::string::npos) return "item";
+        start += 9;
+        size_t inPos = lower.find(" in ", start);
+        if (inPos == std::string::npos) return "item";
+        std::string token = trim(line.substr(start, inPos - start));
+        // "x As Type" => keep x only
+        auto asPos = toLower(token).find(" as ");
+        if (asPos != std::string::npos) token = trim(token.substr(0, asPos));
+        return token.empty() ? "item" : token;
+    }
+
+    static std::string extractMethodName(const std::string& line, const std::string& keyword) {
+        std::string lower = toLower(line);
+        std::string lowerKeyword = toLower(keyword);
+        auto pos = lower.find(lowerKeyword);
+        if (pos == std::string::npos) return "unknown";
+        pos += keyword.size();
+        auto end = line.find('(', pos);
+        if (end == std::string::npos) end = line.find(' ', pos);
+        if (end == std::string::npos) end = line.size();
+        return trim(line.substr(pos, end - pos));
+    }
+
+    static std::string extractDimName(const std::string& line) {
+        auto after = trim(line.substr(4)); // after "Dim "
+        auto asPos = toLower(after).find(" as ");
+        auto eqPos = after.find('=');
+        size_t end = std::string::npos;
+        if (asPos != std::string::npos && eqPos != std::string::npos) end = std::min(asPos, eqPos);
+        else if (asPos != std::string::npos) end = asPos;
+        else if (eqPos != std::string::npos) end = eqPos;
+        if (end == std::string::npos) end = after.size();
+        return trim(after.substr(0, end));
+    }
+
+    static std::string extractNameAfterKeyword(const std::string& line, const std::string& keyword) {
+        auto pos = line.find(keyword);
+        if (pos == std::string::npos) return "unknown";
+        pos += keyword.size();
+        auto end = line.find_first_of("(: ", pos);
+        if (end == std::string::npos) end = line.size();
+        return trim(line.substr(pos, end - pos));
+    }
+
+    static bool startsWithCaseInsensitive(const std::string& s, const std::string& prefix) {
+        if (prefix.size() > s.size()) return false;
+        for (size_t i = 0; i < prefix.size(); ++i) {
+            if (std::tolower(static_cast<unsigned char>(s[i])) !=
+                std::tolower(static_cast<unsigned char>(prefix[i]))) return false;
+        }
+        return true;
+    }
+
+    static bool containsCaseInsensitive(const std::string& s, const std::string& needle) {
+        return toLower(s).find(toLower(needle)) != std::string::npos;
+    }
+
+    static std::string toLower(const std::string& s) {
+        std::string out = s;
+        for (char& c : out) c = static_cast<char>(std::tolower(static_cast<unsigned char>(c)));
+        return out;
+    }
+
+    static std::string trim(const std::string& s) {
+        auto start = s.find_first_not_of(" \t\r\n");
+        if (start == std::string::npos) return "";
+        auto end = s.find_last_not_of(" \t\r\n");
+        return s.substr(start, end - start + 1);
+    }
+};
diff --git a/editor/tests/step407_test.cpp b/editor/tests/step407_test.cpp
new file mode 100644
index 0000000..a5178c0
--- /dev/null
+++ b/editor/tests/step407_test.cpp
@@ -0,0 +1,205 @@
+// Step 407: VB.NET Parser Tests (12 tests)
+
+#include "ast/VBNetParser.h"
+#include "Pipeline.h"
+#include "ast/Function.h"
+#include "ast/Variable.h"
+#include "ast/ClassDeclaration.h"
+#include "ast/EnumNamespaceNodes.h"
+#include "ast/Statement.h"
+
+#include <iostream>
+#include <string>
+
+static int passed = 0, failed = 0;
+#define TEST(name) { std::cout << "  " << #name << "... "; }
+#define PASS() { std::cout << "PASS\n"; ++passed; }
+#define FAIL(msg) { std::cout << "FAIL: " << msg << "\n"; ++failed; }
+#define CHECK(cond, msg) if (!(cond)) { FAIL(msg); return; } else {}
+
+void test_parse_sub_method() {
+    TEST(parse_sub_method);
+    auto mod = VBNetParser::parseVBNet(
+        "Public Sub DoWork(x As Integer)\n"
+        "End Sub\n");
+    CHECK(mod != nullptr, "module is null");
+    auto fns = mod->getChildren("functions");
+    CHECK(fns.size() == 1, "expected 1 function");
+    auto* fn = static_cast<Function*>(fns[0]);
+    CHECK(fn->name == "DoWork", "expected method DoWork");
+    PASS();
+}
+
+void test_parse_function_method() {
+    TEST(parse_function_method);
+    auto mod = VBNetParser::parseVBNet(
+        "Public Function Sum(a As Integer, b As Integer) As Integer\n"
+        "End Function\n");
+    CHECK(mod != nullptr, "module is null");
+    auto fns = mod->getChildren("functions");
+    CHECK(fns.size() == 1, "expected 1 function");
+    auto* fn = static_cast<Function*>(fns[0]);
+    CHECK(fn->name == "Sum", "expected method Sum");
+    PASS();
+}
+
+void test_parse_class() {
+    TEST(parse_class);
+    auto mod = VBNetParser::parseVBNet(
+        "Class Person\n"
+        "End Class\n");
+    CHECK(mod != nullptr, "module is null");
+    auto classes = mod->getChildren("classes");
+    CHECK(classes.size() == 1, "expected 1 class");
+    auto* cls = static_cast<ClassDeclaration*>(classes[0]);
+    CHECK(cls->name == "Person", "expected class Person");
+    PASS();
+}
+
+void test_parse_interface() {
+    TEST(parse_interface);
+    auto mod = VBNetParser::parseVBNet(
+        "Interface IWorker\n"
+        "End Interface\n");
+    CHECK(mod != nullptr, "module is null");
+    auto ifaces = mod->getChildren("interfaces");
+    CHECK(ifaces.size() == 1, "expected 1 interface");
+    auto* iface = static_cast<InterfaceDeclaration*>(ifaces[0]);
+    CHECK(iface->name == "IWorker", "expected interface IWorker");
+    PASS();
+}
+
+void test_parse_module_namespace() {
+    TEST(parse_module_namespace);
+    auto mod = VBNetParser::parseVBNet(
+        "Module Utils\n"
+        "End Module\n");
+    CHECK(mod != nullptr, "module is null");
+    auto stmts = mod->getChildren("statements");
+    NamespaceDeclaration* ns = nullptr;
+    for (auto* s : stmts) {
+        if (s->conceptType == "NamespaceDeclaration") ns = static_cast<NamespaceDeclaration*>(s);
+    }
+    CHECK(ns != nullptr, "expected namespace declaration");
+    CHECK(ns->name == "Utils", "expected module name Utils");
+    PASS();
+}
+
+void test_parse_dim_variable() {
+    TEST(parse_dim_variable);
+    auto mod = VBNetParser::parseVBNet("Dim x As Integer = 5\n");
+    CHECK(mod != nullptr, "module is null");
+    auto vars = mod->getChildren("variables");
+    CHECK(vars.size() == 1, "expected 1 variable");
+    auto* var = static_cast<Variable*>(vars[0]);
+    CHECK(var->name == "x", "expected variable x");
+    PASS();
+}
+
+void test_parse_if_then_block() {
+    TEST(parse_if_then_block);
+    auto mod = VBNetParser::parseVBNet(
+        "If x > 0 Then\n"
+        "ElseIf x < 0 Then\n"
+        "Else\n"
+        "End If\n");
+    CHECK(mod != nullptr, "module is null");
+    bool foundIf = false;
+    for (auto* s : mod->getChildren("statements")) {
+        if (s->conceptType == "IfStatement") foundIf = true;
+    }
+    CHECK(foundIf, "expected IfStatement marker");
+    PASS();
+}
+
+void test_parse_for_each_block() {
+    TEST(parse_for_each_block);
+    auto mod = VBNetParser::parseVBNet(
+        "For Each item In collection\n"
+        "Next\n");
+    CHECK(mod != nullptr, "module is null");
+    bool foundFor = false;
+    for (auto* s : mod->getChildren("statements")) {
+        if (s->conceptType == "ForLoop") {
+            auto* loop = static_cast<ForLoop*>(s);
+            CHECK(loop->iteratorName == "item", "expected iterator item");
+            foundFor = true;
+        }
+    }
+    CHECK(foundFor, "expected ForLoop marker");
+    PASS();
+}
+
+void test_case_insensitive_keywords() {
+    TEST(case_insensitive_keywords);
+    auto mod = VBNetParser::parseVBNet(
+        "public sub Run()\n"
+        "end sub\n");
+    CHECK(mod != nullptr, "module is null");
+    CHECK(mod->getChildren("functions").size() == 1, "expected function with lowercase keyword");
+    PASS();
+}
+
+void test_parse_with_diagnostics() {
+    TEST(parse_with_diagnostics);
+    auto result = VBNetParser::parseVBNetWithDiagnostics(
+        "Function Echo(value As String) As String\n"
+        "End Function\n");
+    CHECK(result.module != nullptr, "module is null");
+    CHECK(result.module->getChildren("functions").size() == 1, "expected 1 function");
+    PASS();
+}
+
+void test_parse_mixed_file() {
+    TEST(parse_mixed_file);
+    auto mod = VBNetParser::parseVBNet(
+        "' comment\n"
+        "Module App\n"
+        "End Module\n"
+        "Class Person\n"
+        "End Class\n"
+        "Public Sub Main()\n"
+        "End Sub\n"
+        "Dim count As Integer = 1\n");
+    CHECK(mod != nullptr, "module is null");
+    CHECK(mod->getChildren("statements").size() >= 1, "expected module statement");
+    CHECK(mod->getChildren("classes").size() == 1, "expected class");
+    CHECK(mod->getChildren("functions").size() == 1, "expected function");
+    CHECK(mod->getChildren("variables").size() == 1, "expected variable");
+    PASS();
+}
+
+void test_pipeline_parse_routing() {
+    TEST(pipeline_parse_routing);
+    Pipeline p;
+    std::vector<ParseDiagnostic> d1, d2, d3;
+    auto m1 = p.parse("Sub Main()\nEnd Sub\n", "vbnet", d1);
+    auto m2 = p.parse("Sub Main()\nEnd Sub\n", "vb", d2);
+    auto m3 = p.parse("Sub Main()\nEnd Sub\n", "vb.net", d3);
+    CHECK(m1 != nullptr && m2 != nullptr && m3 != nullptr, "expected parse success for aliases");
+    CHECK(m1->targetLanguage == "vbnet", "expected vbnet target language");
+    CHECK(m2->targetLanguage == "vbnet", "expected vb alias target language");
+    CHECK(m3->targetLanguage == "vbnet", "expected vb.net alias target language");
+    PASS();
+}
+
+int main() {
+    std::cout << "Step 407: VB.NET Parser Tests\n";
+
+    test_parse_sub_method();       // 1
+    test_parse_function_method();  // 2
+    test_parse_class();            // 3
+    test_parse_interface();        // 4
+    test_parse_module_namespace(); // 5
+    test_parse_dim_variable();     // 6
+    test_parse_if_then_block();    // 7
+    test_parse_for_each_block();   // 8
+    test_case_insensitive_keywords(); // 9
+    test_parse_with_diagnostics(); // 10
+    test_parse_mixed_file();       // 11
+    test_pipeline_parse_routing(); // 12
+
+    std::cout << "\nResults: " << passed << "/" << (passed + failed)
+              << " passed\n";
+    return failed == 0 ? 0 : 1;
+}
diff --git a/progress.md b/progress.md
index c379e23..2645e05 100644
--- a/progress.md
+++ b/progress.md
@@ -3725,6 +3725,54 @@ output, record-style class output, and F#-style type mappings.
   - `editor/src/MCPServer.h` (`1679` > `600`)
   - `editor/src/HeadlessAgentRPCHandler.h` (`2623` > `600`)
 
+### Step 407: VB.NET Parser
+**Status:** PASS (12/12 tests)
+
+Added a standalone VB.NET parser with case-insensitive keyword handling for
+core block forms and declarations. Covers `Sub`/`Function`, `Class`,
+`Interface`, `Module`, `Dim`, `If...Then`, and `For Each...In` recognition.
+
+**Files created:**
+- `editor/src/ast/VBNetParser.h` — VB.NET parse support:
+  - `parseVBNet(...)` and `parseVBNetWithDiagnostics(...)`
+  - `Sub` and `Function` signature extraction
+  - `Class` and `Interface` declaration extraction
+  - `Module` mapping to `NamespaceDeclaration`
+  - `Dim ... As ...` variable extraction
+  - `If ... Then` marker to `IfStatement`
+  - `For Each ... In ...` marker to `ForLoop` with iterator extraction
+  - case-insensitive token matching helpers
+- `editor/tests/step407_test.cpp` — 12 tests covering:
+  1. `Sub` parsing
+  2. `Function` parsing
+  3. class parsing
+  4. interface parsing
+  5. module/namespace parsing
+  6. `Dim` variable parsing
+  7. `If...Then` mapping
+  8. `For Each...In` mapping
+  9. case-insensitive keyword handling
+  10. diagnostics entry point
+  11. mixed-file parsing
+  12. pipeline parse routing for `vbnet` / `vb` / `vb.net`
+
+**Files modified:**
+- `editor/src/ast/Parser.h` — include `ast/VBNetParser.h`
+- `editor/src/Pipeline.h` — parse routing for `vbnet`, `vb`, `vb.net`
+- `editor/CMakeLists.txt` — `step407_test` target
+
+**Verification run:**
+- `step407_test` — PASS (12/12) new step coverage
+- `step406_test` — PASS (12/12) regression coverage
+- `step405_test` — PASS (12/12) regression coverage
+
+**Architecture gate check:**
+- `editor/src/ast/VBNetParser.h` within header-size limit (`184` <= `600`)
+- `editor/tests/step407_test.cpp` within test-file size guidance (`205` lines)
+- Legacy oversized headers persist:
+  - `editor/src/MCPServer.h` (`1679` > `600`)
+  - `editor/src/HeadlessAgentRPCHandler.h` (`2623` > `600`)
+
 # Roadmap Planning — Sprints 12-25+
 
 ## Status: Planning Complete (Sprints 12-19 detailed, 20-25 in roadmap.md)