diff --git a/Sources/SwiftDoc/Helpers.swift b/Sources/SwiftDoc/Helpers.swift
index d23e8384..3541fcaf 100644
--- a/Sources/SwiftDoc/Helpers.swift
+++ b/Sources/SwiftDoc/Helpers.swift
@@ -14,10 +14,20 @@ public func path(for symbol: Symbol, with baseURL: String) -> String {
 }
 
 public func path(for identifier: CustomStringConvertible, with baseURL: String) -> String {
-    let url = URL(string: baseURL)?.appendingPathComponent("\(identifier)") ?? URL(string: "\(identifier)")
+    let tail: String = path(for: "\(identifier)")
+    let url = URL(string: baseURL)?.appendingPathComponent(tail) ?? URL(string: tail)
     guard let string = url?.absoluteString else {
         fatalError("Unable to construct path for \(identifier) with baseURL \(baseURL)")
     }
 
     return string
 }
+
+private let reservedCharacters: CharacterSet = [
+    // Windows Reserved Characters
+    "<", ">", ":", "\"", "/", "\\", "|", "?", "*",
+]
+
+public func path(for identifier: String) -> String {
+    return identifier.components(separatedBy: reservedCharacters).joined(separator: "_")
+}
diff --git a/Sources/swift-doc/Subcommands/Generate.swift b/Sources/swift-doc/Subcommands/Generate.swift
index 82c9ef32..52ac8e28 100644
--- a/Sources/swift-doc/Subcommands/Generate.swift
+++ b/Sources/swift-doc/Subcommands/Generate.swift
@@ -134,11 +134,11 @@ extension SwiftDoc {
             let filename: String
             switch format {
             case .commonmark:
-              filename = "\($0.key).md"
+              filename = "\(path(for: $0.key)).md"
             case .html where $0.key == "Home":
               filename = "index.html"
             case .html:
-              filename = "\($0.key)/index.html"
+              filename = "\(path(for: $0.key))/index.html"
             }
 
             let url = outputDirectoryURL.appendingPathComponent(filename)
diff --git a/Tests/SwiftDocTests/PathTests.swift b/Tests/SwiftDocTests/PathTests.swift
index a33804d7..1c586af0 100644
--- a/Tests/SwiftDocTests/PathTests.swift
+++ b/Tests/SwiftDocTests/PathTests.swift
@@ -6,42 +6,42 @@ final class PathTests: XCTestCase {
     func testEmptyBaseURL() {
         XCTAssertEqual(path(for: "Class", with: ""), "Class")
 
-        XCTAssertEqual(path(for: "(lhs:rhs:)", with: ""), "(lhs:rhs:)")
+        XCTAssertEqual(path(for: "(lhs:rhs:)", with: ""), "(lhs_rhs_)")
     }
 
     func testRootDirectoryBaseURL() {
         XCTAssertEqual(path(for: "Class", with: "/"), "/Class")
 
-        XCTAssertEqual(path(for: "(lhs:rhs:)", with: "/"), "/(lhs:rhs:)")
+        XCTAssertEqual(path(for: "(lhs:rhs:)", with: "/"), "/(lhs_rhs_)")
     }
 
     func testCurrentDirectoryBaseURL() {
         XCTAssertEqual(path(for: "Class", with: "./"), "./Class")
 
-        XCTAssertEqual(path(for: "(lhs:rhs:)", with: "./"), "./(lhs:rhs:)")
+        XCTAssertEqual(path(for: "(lhs:rhs:)", with: "./"), "./(lhs_rhs_)")
     }
 
     func testNestedSubdirectoryBaseURL() {
         XCTAssertEqual(path(for: "Class", with: "/path/to/directory"), "/path/to/directory/Class")
         XCTAssertEqual(path(for: "Class", with: "/path/to/directory/"), "/path/to/directory/Class")
 
-        XCTAssertEqual(path(for: "(lhs:rhs:)", with: "/path/to/directory"), "/path/to/directory/(lhs:rhs:)")
-        XCTAssertEqual(path(for: "(lhs:rhs:)", with: "/path/to/directory/"), "/path/to/directory/(lhs:rhs:)")
+        XCTAssertEqual(path(for: "(lhs:rhs:)", with: "/path/to/directory"), "/path/to/directory/(lhs_rhs_)")
+        XCTAssertEqual(path(for: "(lhs:rhs:)", with: "/path/to/directory/"), "/path/to/directory/(lhs_rhs_)")
     }
 
     func testDomainBaseURL() {
         XCTAssertEqual(path(for: "Class", with: "https://example.com"), "https://example.com/Class")
         XCTAssertEqual(path(for: "Class", with: "https://example.com/"), "https://example.com/Class")
 
-        XCTAssertEqual(path(for: "(lhs:rhs:)", with: "https://example.com"), "https://example.com/(lhs:rhs:)")
-        XCTAssertEqual(path(for: "(lhs:rhs:)", with: "https://example.com/"), "https://example.com/(lhs:rhs:)")
+        XCTAssertEqual(path(for: "(lhs:rhs:)", with: "https://example.com"), "https://example.com/(lhs_rhs_)")
+        XCTAssertEqual(path(for: "(lhs:rhs:)", with: "https://example.com/"), "https://example.com/(lhs_rhs_)")
     }
 
     func testDomainSubdirectoryBaseURL() {
         XCTAssertEqual(path(for: "Class", with: "https://example.com/docs"), "https://example.com/docs/Class")
         XCTAssertEqual(path(for: "Class", with: "https://example.com/docs/"), "https://example.com/docs/Class")
 
-        XCTAssertEqual(path(for: "(lhs:rhs:)", with: "https://example.com/docs"), "https://example.com/docs/(lhs:rhs:)")
-        XCTAssertEqual(path(for: "(lhs:rhs:)", with: "https://example.com/docs/"), "https://example.com/docs/(lhs:rhs:)")
+        XCTAssertEqual(path(for: "(lhs:rhs:)", with: "https://example.com/docs"), "https://example.com/docs/(lhs_rhs_)")
+        XCTAssertEqual(path(for: "(lhs:rhs:)", with: "https://example.com/docs/"), "https://example.com/docs/(lhs_rhs_)")
     }
 }