diff --git a/src/main/kotlin/fr/postgresjson/definition/parse/ParsingFunction.kt b/src/main/kotlin/fr/postgresjson/definition/parse/ParsingFunction.kt
index 9b5b749..5a947fa 100644
--- a/src/main/kotlin/fr/postgresjson/definition/parse/ParsingFunction.kt
+++ b/src/main/kotlin/fr/postgresjson/definition/parse/ParsingFunction.kt
@@ -32,6 +32,7 @@ internal fun parseFunction(script: String, source: Path? = null): Function {
 internal fun ScriptPart.getFunctionName(): NextScript<String> {
     try {
         return getNextScript { status.isNotEscaped() && afterBeginBy("(", " ", "\n") }
+            .changeValue { unescapeOrLowercase() }
     } catch (e: ParseException) {
         throw FunctionNameMalformed(this, e)
     }
@@ -95,6 +96,7 @@ private fun ScriptPart.getParameterMode(): NextScript<Direction> {
 private fun ScriptPart.getParameterName(): NextScript<String> {
     try {
         return getNextScript { afterBeginBy(" ", "\n") && status.isNotEscaped() }
+            .changeValue { unescapeOrLowercase() }
     } catch (e: ParseException) {
         throw ParameterNameMalformed(this, e)
     }
diff --git a/src/main/kotlin/fr/postgresjson/definition/parse/ParsingHelper.kt b/src/main/kotlin/fr/postgresjson/definition/parse/ParsingHelper.kt
index e718113..1e73829 100644
--- a/src/main/kotlin/fr/postgresjson/definition/parse/ParsingHelper.kt
+++ b/src/main/kotlin/fr/postgresjson/definition/parse/ParsingHelper.kt
@@ -61,7 +61,7 @@ internal fun ScriptPart.getNextScript(isEnd: Context.() -> Boolean = { false }):
 
         if (isEnd(Context(index, c, status.copy(), restOfScript))) {
             return NextScript(
-                restOfScript.take(index + 1).unescape(),
+                restOfScript.take(index + 1),
                 restOfScript.drop(index + 1),
             )
         }
@@ -77,13 +77,19 @@ internal fun ScriptPart.getNextScript(isEnd: Context.() -> Boolean = { false }):
     throw ParseError()
 }
 
-private fun String.unescape(): String {
+internal fun ScriptPart.unescapeOrLowercase(): ScriptPart = restOfScript
+    .run(String::unescapeOrLowercase)
+    .let(::ScriptPart)
+
+internal fun String.unescapeOrLowercase(): String {
     val first = take(1)
     val last = takeLast(1)
-    return if (first == last && first in listOf("\"", "'")) {
+    return if (first == last && first == "'") {
+        drop(1).dropLast(1).replace("$first$first", first).lowercase()
+    } else if (first == last && first == "\"") {
         drop(1).dropLast(1).replace("$first$first", first)
     } else {
-        this
+        this.lowercase()
     }
 }
 
@@ -142,6 +148,14 @@ internal inline fun ScriptPart.change(block: String.() -> String): ScriptPart {
     return ScriptPart(restOfScript.run(block))
 }
 
+@OptIn(ExperimentalContracts::class)
+internal inline fun <T> NextScript<T>.changeValue(block: T.() -> T): NextScript<T> {
+    contract {
+        callsInPlace(block, EXACTLY_ONCE)
+    }
+    return NextScript(value.run(block), nextScriptPart.restOfScript)
+}
+
 internal fun ScriptPart.getNextInteger(): NextScript<Int?> {
     val digits = restOfScript.takeWhile { it.isDigit() }
     val restOfScript = restOfScript.trimStart { it.isDigit() }
diff --git a/src/test/kotlin/fr/postgresjson/definition/FunctionTest.kt b/src/test/kotlin/fr/postgresjson/definition/FunctionTest.kt
index 0a40efc..8471c9e 100644
--- a/src/test/kotlin/fr/postgresjson/definition/FunctionTest.kt
+++ b/src/test/kotlin/fr/postgresjson/definition/FunctionTest.kt
@@ -24,7 +24,7 @@ class FunctionTest : FreeSpec({
             }
         }
 
-        "first letter caps" {
+        "first letter caps without quoted" {
             parseFunction(
                 // language=PostgreSQL
                 """
@@ -32,7 +32,7 @@ class FunctionTest : FreeSpec({
                 $$ begin; end$$;
                 """.trimIndent()
             ).apply {
-                name shouldBe "Myfun"
+                name shouldBe "myfun"
             }
         }
 
@@ -60,7 +60,7 @@ class FunctionTest : FreeSpec({
             }
         }
 
-        "escaped name with double quote in name" {
+        "quoted name with double quote in name" {
             parseFunction(
                 // language=PostgreSQL
                 """
@@ -153,6 +153,20 @@ class FunctionTest : FreeSpec({
                 param[1].name shouldBe "#@€"
             }
         }
+        "Parameters with Caps" - {
+            val param = parseFunction(
+                // language=PostgreSQL
+                """
+                create or replace function myfun("One" text, Two text) returns text language plpgsql as
+                $$ begin end;$$;
+                """.trimIndent()
+            ).parameters
+
+            "should have first parameter name" {
+                param[0].name shouldBe "One"
+                param[1].name shouldBe "two"
+            }
+        }
 
         "Parameters with type `character varying(255)`" - {
             val param = parseFunction(