diff --git a/clang/lib/Format/ContinuationIndenter.cpp b/clang/lib/Format/ContinuationIndenter.cpp
--- a/clang/lib/Format/ContinuationIndenter.cpp
+++ b/clang/lib/Format/ContinuationIndenter.cpp
@@ -1047,6 +1047,9 @@
   if (NextNonComment->is(TT_ArraySubscriptLSquare)) {
     if (State.Stack.back().StartOfArraySubscripts != 0)
       return State.Stack.back().StartOfArraySubscripts;
+    else if (Style.isCSharp()) // C# allows `["key"] = value` inside object
+                               // initializers.
+      return State.Stack.back().Indent;
     return ContinuationIndent;
   }
 
diff --git a/clang/unittests/Format/FormatTestCSharp.cpp b/clang/unittests/Format/FormatTestCSharp.cpp
--- a/clang/unittests/Format/FormatTestCSharp.cpp
+++ b/clang/unittests/Format/FormatTestCSharp.cpp
@@ -551,6 +551,15 @@
   Scaler = (Shape shape) => { return new Transform.Resize(shape, 0.1); },
 };)",
                Style);
+
+  // Dictionary initialisation.
+  verifyFormat(R"(//
+var myDict = new Dictionary<string, string> {
+  ["name"] = _donald,
+  ["age"] = Convert.ToString(DateTime.Today.Year - 1934),
+  ["type"] = _duck,
+};)",
+               Style);
 }
 
 TEST_F(FormatTestCSharp, CSharpNamedArguments) {