diff --git a/stdlib/LinearAlgebra/src/diagonal.jl b/stdlib/LinearAlgebra/src/diagonal.jl
index b3826a2aa7f82..ff8350d8ddeb1 100644
--- a/stdlib/LinearAlgebra/src/diagonal.jl
+++ b/stdlib/LinearAlgebra/src/diagonal.jl
@@ -268,10 +268,10 @@ end
 (-)(Da::Diagonal, Db::Diagonal) = Diagonal(Da.diag - Db.diag)
 
 for f in (:+, :-)
-    @eval function $f(D::Diagonal, S::Symmetric)
+    @eval function $f(D::Diagonal{<:Number}, S::Symmetric)
         return Symmetric($f(D, S.data), sym_uplo(S.uplo))
     end
-    @eval function $f(S::Symmetric, D::Diagonal)
+    @eval function $f(S::Symmetric, D::Diagonal{<:Number})
         return Symmetric($f(S.data, D), sym_uplo(S.uplo))
     end
     @eval function $f(D::Diagonal{<:Real}, H::Hermitian)
diff --git a/stdlib/LinearAlgebra/test/diagonal.jl b/stdlib/LinearAlgebra/test/diagonal.jl
index 1a3b8d4fd0ea7..e1fc9afa5ad2e 100644
--- a/stdlib/LinearAlgebra/test/diagonal.jl
+++ b/stdlib/LinearAlgebra/test/diagonal.jl
@@ -1335,4 +1335,16 @@ end
     end
 end
 
+@testset "+/- with block Symmetric/Hermitian" begin
+    for p in ([1 2; 3 4], [1 2+im; 2-im 4+2im])
+        m = SizedArrays.SizedArray{(2,2)}(p)
+        D = Diagonal(fill(m, 2))
+        for T in (Symmetric, Hermitian)
+            S = T(fill(m, 2, 2))
+            @test D + S == Array(D) + Array(S)
+            @test S + D == Array(S) + Array(D)
+        end
+    end
+end
+
 end # module TestDiagonal