diff --git a/Sources/Splash/Grammar/SwiftGrammar.swift b/Sources/Splash/Grammar/SwiftGrammar.swift
index 1d3942f..df6225c 100644
--- a/Sources/Splash/Grammar/SwiftGrammar.swift
+++ b/Sources/Splash/Grammar/SwiftGrammar.swift
@@ -41,7 +41,7 @@ private extension SwiftGrammar {
         "final", "class", "struct", "enum", "protocol",
         "extension", "let", "var", "func", "typealias",
         "init", "guard", "if", "else", "return", "get",
-        "throw", "throws", "for", "in", "open", "weak",
+        "throw", "throws", "rethrows", "for", "in", "open", "weak",
         "import", "mutating", "nonmutating", "associatedtype",
         "case", "switch", "static", "do", "try", "catch", "as",
         "super", "self", "set", "true", "false", "nil",
diff --git a/Tests/SplashTests/Tests/DeclarationTests.swift b/Tests/SplashTests/Tests/DeclarationTests.swift
index 688f8e3..664d274 100644
--- a/Tests/SplashTests/Tests/DeclarationTests.swift
+++ b/Tests/SplashTests/Tests/DeclarationTests.swift
@@ -635,7 +635,7 @@ final class DeclarationTests: SyntaxHighlighterTestCase {
             .token("inout", .keyword),
             .whitespace(" "),
             .token("Int", .type),
-			.plainText(")"),
+            .plainText(")"),
             .whitespace(" "),
             .plainText("{"),
             .whitespace(" "),
@@ -750,6 +750,40 @@ final class DeclarationTests: SyntaxHighlighterTestCase {
         ])
     }
 
+    func testRethrowingFunctionDeclaration() {
+        let components = highlighter.highlight("""
+        func map<T>(_ transform: (Element) throws -> T) rethrows -> [T]
+        """)
+
+        XCTAssertEqual(components, [
+            .token("func", .keyword),
+            .whitespace(" "),
+            .plainText("map<T>("),
+            .token("_", .keyword),
+            .whitespace(" "),
+            .plainText("transform:"),
+            .whitespace(" "),
+            .plainText("("),
+            .token("Element", .type),
+            .plainText(")"),
+            .whitespace(" "),
+            .token("throws", .keyword),
+            .whitespace(" "),
+            .plainText("->"),
+            .whitespace(" "),
+            .token("T", .type),
+            .plainText(")"),
+            .whitespace(" "),
+            .token("rethrows", .keyword),
+            .whitespace(" "),
+            .plainText("->"),
+            .whitespace(" "),
+            .plainText("["),
+            .token("T", .type),
+            .plainText("]")
+        ])
+    }
+
     func testIndirectEnumDeclaration() {
         let components = highlighter.highlight("""
         indirect enum Content {
@@ -822,6 +856,7 @@ extension DeclarationTests {
             ("testFunctionDeclarationWithEscapedKeywordAsName", testFunctionDeclarationWithEscapedKeywordAsName),
             ("testFunctionDeclarationWithPreProcessors", testFunctionDeclarationWithPreProcessors),
             ("testNonMutatingFunction", testNonMutatingFunction),
+            ("testRethrowingFunctionDeclaration", testRethrowingFunctionDeclaration),
             ("testIndirectEnumDeclaration", testIndirectEnumDeclaration)
         ]
     }