diff --git a/src/features/completion/component_environment.rs b/src/features/completion/component_environment.rs
index d4340a16..ce2891e5 100644
--- a/src/features/completion/component_environment.rs
+++ b/src/features/completion/component_environment.rs
@@ -155,4 +155,24 @@ mod tests {
             assert_eq!(item.range, TextRange::new(7.into(), 8.into()));
         }
     }
+
+    #[test]
+    fn test_command_definition() {
+        let request = FeatureTester::builder()
+            .files(vec![("main.tex", "\\newcommand{\\foo}{\\begin{\nd}")])
+            .main("main.tex")
+            .line(1)
+            .character(1)
+            .build()
+            .completion();
+
+        let context = CursorContext::new(request);
+        let mut actual_items = Vec::new();
+        complete_component_environments(&context, &mut actual_items, CancellationToken::none());
+
+        assert!(!actual_items.is_empty());
+        for item in actual_items {
+            assert_eq!(item.range, TextRange::new(26.into(), 27.into()));
+        }
+    }
 }
diff --git a/src/syntax/latex/parser.rs b/src/syntax/latex/parser.rs
index 8dc7fa9b..ac73113a 100644
--- a/src/syntax/latex/parser.rs
+++ b/src/syntax/latex/parser.rs
@@ -189,6 +189,21 @@ impl<'a> Parser<'a> {
         self.builder.finish_node();
     }
 
+    fn curly_group_impl(&mut self) {
+        self.builder.start_node(CURLY_GROUP.into());
+        self.eat();
+        while let Some(kind) = self.peek() {
+            match kind {
+                R_CURLY => break,
+                BEGIN_ENVIRONMENT_NAME => self.begin(),
+                END_ENVIRONMENT_NAME => self.end(),
+                _ => self.content(ParserContext::default()),
+            };
+        }
+        self.expect(R_CURLY);
+        self.builder.finish_node();
+    }
+
     fn curly_group_without_environments(&mut self) {
         self.builder.start_node(CURLY_GROUP.into());
         self.eat();
@@ -1020,7 +1035,7 @@ impl<'a> Parser<'a> {
         }
 
         if self.lexer.peek() == Some(L_CURLY) {
-            self.curly_group();
+            self.curly_group_impl();
         } else {
             self.builder.token(MISSING.into(), "");
         }
@@ -1040,7 +1055,7 @@ impl<'a> Parser<'a> {
         }
 
         if self.lexer.peek() == Some(L_CURLY) {
-            self.curly_group();
+            self.curly_group_impl();
         } else {
             self.builder.token(MISSING.into(), "");
         }
@@ -1703,6 +1718,13 @@ mod tests {
         assert_debug_snapshot!(setup(r#"\newcommand{\foo"#));
     }
 
+    #[test]
+    fn test_command_definition_with_begin() {
+        assert_debug_snapshot!(setup(
+            r#"\newcommand{\CVSubHeadingListStart}{\begin{itemize}[leftmargin=0.5cm, label={}]}"#
+        ));
+    }
+
     #[test]
     fn test_math_operator_simple() {
         assert_debug_snapshot!(setup(r#"\DeclareMathOperator{\foo}{foo}"#));
diff --git a/src/syntax/latex/snapshots/texlab__syntax__latex__parser__tests__command_definition_with_begin.snap b/src/syntax/latex/snapshots/texlab__syntax__latex__parser__tests__command_definition_with_begin.snap
new file mode 100644
index 00000000..6b7724c0
--- /dev/null
+++ b/src/syntax/latex/snapshots/texlab__syntax__latex__parser__tests__command_definition_with_begin.snap
@@ -0,0 +1,39 @@
+---
+source: src/syntax/latex/parser.rs
+assertion_line: 1723
+expression: "setup(r#\"\\newcommand{\\CVSubHeadingListStart}{\\begin{itemize}[leftmargin=0.5cm, label={}]}\"#)"
+---
+ROOT@0..80
+  PREAMBLE@0..80
+    COMMAND_DEFINITION@0..80
+      COMMAND_DEFINITION_NAME@0..11 "\\newcommand"
+      CURLY_GROUP_COMMAND@11..35
+        L_CURLY@11..12 "{"
+        GENERIC_COMMAND_NAME@12..34 "\\CVSubHeadingListStart"
+        R_CURLY@34..35 "}"
+      CURLY_GROUP@35..80
+        L_CURLY@35..36 "{"
+        BEGIN@36..79
+          BEGIN_ENVIRONMENT_NAME@36..42 "\\begin"
+          CURLY_GROUP_WORD@42..51
+            L_CURLY@42..43 "{"
+            KEY@43..50
+              WORD@43..50 "itemize"
+            R_CURLY@50..51 "}"
+          BRACK_GROUP@51..79
+            L_BRACK@51..52 "["
+            TEXT@52..62
+              WORD@52..62 "leftmargin"
+            EQUALITY_SIGN@62..63 "="
+            TEXT@63..75
+              WORD@63..68 "0.5cm"
+              COMMA@68..69 ","
+              WHITESPACE@69..70 " "
+              WORD@70..75 "label"
+            EQUALITY_SIGN@75..76 "="
+            CURLY_GROUP@76..78
+              L_CURLY@76..77 "{"
+              R_CURLY@77..78 "}"
+            R_BRACK@78..79 "]"
+        R_CURLY@79..80 "}"
+