diff --git a/parser/v2/types.go b/parser/v2/types.go
index 9dd2f054a..38eedefde 100644
--- a/parser/v2/types.go
+++ b/parser/v2/types.go
@@ -1,6 +1,7 @@
 package parser
 
 import (
+	"bytes"
 	"errors"
 	"fmt"
 	"go/format"
@@ -155,16 +156,21 @@ func (exp GoExpression) Write(w io.Writer, indent int) error {
 	if err != nil {
 		return writeIndent(w, indent, exp.Expression.Value)
 	}
-
 	_, err = w.Write(data)
 	return err
 }
 
-func writeIndent(w io.Writer, level int, s string) (err error) {
-	if _, err = w.Write([]byte(strings.Repeat("\t", level))); err != nil {
-		return
+func writeIndent(w io.Writer, level int, s ...string) (err error) {
+	indent := strings.Repeat("\t", level)
+	if _, err = io.WriteString(w, indent); err != nil {
+		return err
+	}
+	for _, ss := range s {
+		_, err = io.WriteString(w, ss)
+		if err != nil {
+			return
+		}
 	}
-	_, err = w.Write([]byte(s))
 	return
 }
 
@@ -216,7 +222,7 @@ type CSSTemplate struct {
 
 func (css CSSTemplate) IsTemplateFileNode() bool { return true }
 func (css CSSTemplate) Write(w io.Writer, indent int) error {
-	if err := writeIndent(w, indent, "css "+css.Name.Value+"() {\n"); err != nil {
+	if err := writeIndent(w, indent, "css ", css.Name.Value, "() {\n"); err != nil {
 		return err
 	}
 	for _, p := range css.Properties {
@@ -273,7 +279,7 @@ type ExpressionCSSProperty struct {
 
 func (c ExpressionCSSProperty) IsCSSProperty() bool { return true }
 func (c ExpressionCSSProperty) Write(w io.Writer, indent int) error {
-	if err := writeIndent(w, indent, c.Name+": "); err != nil {
+	if err := writeIndent(w, indent, c.Name, ": "); err != nil {
 		return err
 	}
 	if err := c.Value.Write(w, 0); err != nil {
@@ -292,7 +298,7 @@ type DocType struct {
 
 func (dt DocType) IsNode() bool { return true }
 func (dt DocType) Write(w io.Writer, indent int) error {
-	return writeIndent(w, indent, "<!DOCTYPE "+dt.Value+">")
+	return writeIndent(w, indent, "<!DOCTYPE ", dt.Value, ">")
 }
 
 // HTMLTemplate definition.
@@ -310,7 +316,7 @@ type HTMLTemplate struct {
 func (t HTMLTemplate) IsTemplateFileNode() bool { return true }
 
 func (t HTMLTemplate) Write(w io.Writer, indent int) error {
-	if err := writeIndent(w, indent, "templ "+t.Expression.Value+" {\n"); err != nil {
+	if err := writeIndent(w, indent, "templ ", t.Expression.Value, " {\n"); err != nil {
 		return err
 	}
 	if err := writeNodesIndented(w, indent+1, t.Children); err != nil {
@@ -462,7 +468,7 @@ func containsNonTextNodes(nodes []Node) bool {
 
 func (e Element) IsNode() bool { return true }
 func (e Element) Write(w io.Writer, indent int) error {
-	if err := writeIndent(w, indent, "<"+e.Name); err != nil {
+	if err := writeIndent(w, indent, "<", e.Name); err != nil {
 		return err
 	}
 	for i := 0; i < len(e.Attributes); i++ {
@@ -497,7 +503,7 @@ func (e Element) Write(w io.Writer, indent int) error {
 			if err := writeNodesIndented(w, indent+1, e.Children); err != nil {
 				return err
 			}
-			if err := writeIndent(w, indent, "</"+e.Name+">"); err != nil {
+			if err := writeIndent(w, indent, "</", e.Name, ">"); err != nil {
 				return err
 			}
 			return nil
@@ -519,7 +525,7 @@ func (e Element) Write(w io.Writer, indent int) error {
 		}
 		return nil
 	}
-	if err := writeIndent(w, closeAngleBracketIndent, "></"+e.Name+">"); err != nil {
+	if err := writeIndent(w, closeAngleBracketIndent, "></", e.Name, ">"); err != nil {
 		return err
 	}
 	return nil
@@ -607,7 +613,7 @@ type RawElement struct {
 func (e RawElement) IsNode() bool { return true }
 func (e RawElement) Write(w io.Writer, indent int) error {
 	// Start.
-	if err := writeIndent(w, indent, "<"+e.Name); err != nil {
+	if err := writeIndent(w, indent, "<", e.Name); err != nil {
 		return err
 	}
 	for i := 0; i < len(e.Attributes); i++ {
@@ -687,11 +693,55 @@ type ExpressionAttribute struct {
 }
 
 func (ea ExpressionAttribute) String() string {
-	return ea.Name + `={ ` + ea.Expression.Value + ` }`
+	sb := new(strings.Builder)
+	ea.Write(sb, 0)
+	return sb.String()
 }
 
-func (ea ExpressionAttribute) Write(w io.Writer, indent int) error {
-	return writeIndent(w, indent, ea.String())
+func (ea ExpressionAttribute) formatExpression() (exp []string) {
+	trimmed := strings.TrimSpace(ea.Expression.Value)
+	if !strings.Contains(trimmed, "\n") {
+		formatted, err := format.Source([]byte(trimmed))
+		if err != nil {
+			return []string{trimmed}
+		}
+		return []string{string(formatted)}
+	}
+
+	buf := bytes.NewBufferString("[]any{\n")
+	buf.WriteString(trimmed)
+	buf.WriteString("\n}")
+
+	formatted, err := format.Source(buf.Bytes())
+	if err != nil {
+		return []string{trimmed}
+	}
+
+	// Trim prefix and suffix.
+	lines := strings.Split(string(formatted), "\n")
+	if len(lines) < 3 {
+		return []string{trimmed}
+	}
+
+	// Return.
+	return lines[1 : len(lines)-1]
+}
+
+func (ea ExpressionAttribute) Write(w io.Writer, indent int) (err error) {
+	lines := ea.formatExpression()
+	if len(lines) == 1 {
+		return writeIndent(w, indent, ea.Name, `={ `, lines[0], ` }`)
+	}
+
+	if err = writeIndent(w, indent, ea.Name, "={\n"); err != nil {
+		return err
+	}
+	for _, line := range lines {
+		if err = writeIndent(w, indent, line, "\n"); err != nil {
+			return err
+		}
+	}
+	return writeIndent(w, indent, "}")
 }
 
 //	<a href="test" \
@@ -769,9 +819,9 @@ type GoComment struct {
 func (c GoComment) IsNode() bool { return true }
 func (c GoComment) Write(w io.Writer, indent int) error {
 	if c.Multiline {
-		return writeIndent(w, indent, "/*"+c.Contents+"*/")
+		return writeIndent(w, indent, "/*", c.Contents, "*/")
 	}
-	return writeIndent(w, indent, "//"+c.Contents)
+	return writeIndent(w, indent, "//", c.Contents)
 }
 
 // HTMLComment.
@@ -781,7 +831,7 @@ type HTMLComment struct {
 
 func (c HTMLComment) IsNode() bool { return true }
 func (c HTMLComment) Write(w io.Writer, indent int) error {
-	return writeIndent(w, indent, "<!--"+c.Contents+"-->")
+	return writeIndent(w, indent, "<!--", c.Contents, "-->")
 }
 
 // Nodes.
@@ -797,7 +847,7 @@ type CallTemplateExpression struct {
 
 func (cte CallTemplateExpression) IsNode() bool { return true }
 func (cte CallTemplateExpression) Write(w io.Writer, indent int) error {
-	return writeIndent(w, indent, `{! `+cte.Expression.Value+` }`)
+	return writeIndent(w, indent, `{! `, cte.Expression.Value, ` }`)
 }
 
 // TemplElementExpression can be used to create and render a template using data.
@@ -856,7 +906,7 @@ type ElseIfExpression struct {
 
 func (n IfExpression) IsNode() bool { return true }
 func (n IfExpression) Write(w io.Writer, indent int) error {
-	if err := writeIndent(w, indent, "if "+n.Expression.Value+" {\n"); err != nil {
+	if err := writeIndent(w, indent, "if ", n.Expression.Value, " {\n"); err != nil {
 		return err
 	}
 	indent++
@@ -865,7 +915,7 @@ func (n IfExpression) Write(w io.Writer, indent int) error {
 	}
 	indent--
 	for _, elseIf := range n.ElseIfs {
-		if err := writeIndent(w, indent, "} else if "+elseIf.Expression.Value+" {\n"); err != nil {
+		if err := writeIndent(w, indent, "} else if ", elseIf.Expression.Value, " {\n"); err != nil {
 			return err
 		}
 		indent++
@@ -898,13 +948,13 @@ type SwitchExpression struct {
 
 func (se SwitchExpression) IsNode() bool { return true }
 func (se SwitchExpression) Write(w io.Writer, indent int) error {
-	if err := writeIndent(w, indent, "switch "+se.Expression.Value+" {\n"); err != nil {
+	if err := writeIndent(w, indent, "switch ", se.Expression.Value, " {\n"); err != nil {
 		return err
 	}
 	indent++
 	for i := 0; i < len(se.Cases); i++ {
 		c := se.Cases[i]
-		if err := writeIndent(w, indent, c.Expression.Value+"\n"); err != nil {
+		if err := writeIndent(w, indent, c.Expression.Value, "\n"); err != nil {
 			return err
 		}
 		if err := writeNodesIndented(w, indent+1, c.Children); err != nil {
@@ -934,7 +984,7 @@ type ForExpression struct {
 
 func (fe ForExpression) IsNode() bool { return true }
 func (fe ForExpression) Write(w io.Writer, indent int) error {
-	if err := writeIndent(w, indent, "for "+fe.Expression.Value+" {\n"); err != nil {
+	if err := writeIndent(w, indent, "for ", fe.Expression.Value, " {\n"); err != nil {
 		return err
 	}
 	if err := writeNodesIndented(w, indent+1, fe.Children); err != nil {
@@ -961,7 +1011,7 @@ func (se StringExpression) Trailing() TrailingSpace {
 func (se StringExpression) IsNode() bool                  { return true }
 func (se StringExpression) IsStyleDeclarationValue() bool { return true }
 func (se StringExpression) Write(w io.Writer, indent int) error {
-	return writeIndent(w, indent, `{ `+se.Expression.Value+` }`)
+	return writeIndent(w, indent, `{ `, se.Expression.Value, ` }`)
 }
 
 // ScriptTemplate is a script block.
@@ -973,7 +1023,7 @@ type ScriptTemplate struct {
 
 func (s ScriptTemplate) IsTemplateFileNode() bool { return true }
 func (s ScriptTemplate) Write(w io.Writer, indent int) error {
-	if err := writeIndent(w, indent, "script "+s.Name.Value+"("+s.Parameters.Value+") {\n"); err != nil {
+	if err := writeIndent(w, indent, "script ", s.Name.Value, "(", s.Parameters.Value, ") {\n"); err != nil {
 		return err
 	}
 	if _, err := io.WriteString(w, s.Value); err != nil {
diff --git a/parser/v2/types_test.go b/parser/v2/types_test.go
index 1b6f17ce0..85af99c12 100644
--- a/parser/v2/types_test.go
+++ b/parser/v2/types_test.go
@@ -539,6 +539,45 @@ templ x() {
 		</a>
 	</li>
 }
+`,
+		},
+		{
+			name: "templ expression attribute are formatted correctly when multiline",
+			input: ` // first line removed to make indentation clear
+package main
+
+templ x(id string, class string) {
+<button
+id={id}
+name={
+      "name"
+  }
+class={ 
+      "blue",
+    class,
+		map[string]bool{
+		"a": true,
+		},
+}
+></button>
+}
+`,
+			expected: ` // first line removed to make indentation clear
+package main
+
+templ x(id string, class string) {
+	<button
+ 		id={ id }
+ 		name={ "name" }
+ 		class={
+			"blue",
+			class,
+			map[string]bool{
+				"a": true,
+			},
+		}
+	></button>
+}
 `,
 		},
 		{