diff --git a/base/promotion.jl b/base/promotion.jl
index 469eb0bd8e4a8..13b50366e1d2b 100644
--- a/base/promotion.jl
+++ b/base/promotion.jl
@@ -84,22 +84,35 @@ function typejoin(@nospecialize(a), @nospecialize(b))
             while a.name !== b.name
                 a = supertype(a)
             end
-            aprimary = unwrap_unionall(a.name.wrapper)
+            if a.name === Type.body.name
+                ap = a.parameters[1]
+                bp = b.parameters[1]
+                if ((isa(ap,TypeVar) && ap.lb === Bottom && ap.ub === Any) ||
+                    (isa(bp,TypeVar) && bp.lb === Bottom && bp.ub === Any))
+                    # handle special Type{T} supertype
+                    return Type
+                end
+            end
+            aprimary = a.name.wrapper
             # join on parameters
             n = length(a.parameters)
             if n == 0
                 return aprimary
             end
-            p = Vector{Any}(undef, n)
+            vars = []
             for i = 1:n
                 ai, bi = a.parameters[i], b.parameters[i]
                 if ai === bi || (isa(ai,Type) && isa(bi,Type) && typeseq(ai,bi))
-                    p[i] = ai
+                    aprimary = aprimary{ai}
                 else
-                    p[i] = aprimary.parameters[i]
+                    pushfirst!(vars, aprimary.var)
+                    aprimary = aprimary.body
                 end
             end
-            return rewrap_unionall(a.name.wrapper{p...}, a.name.wrapper)
+            for v in vars
+                aprimary = UnionAll(v, aprimary)
+            end
+            return aprimary
         end
         b = supertype(b)
     end
diff --git a/test/core.jl b/test/core.jl
index 844e6abf0f53a..661fd3914f2fc 100644
--- a/test/core.jl
+++ b/test/core.jl
@@ -127,6 +127,20 @@ end
 @test typejoin(Tuple{Vararg{Int,2}}, Tuple{Int,Int,Int}) === Tuple{Int,Int,Vararg{Int}}
 @test typejoin(Tuple{Vararg{Int,2}}, Tuple{Vararg{Int}}) === Tuple{Vararg{Int}}
 
+# issue #26321
+struct T26321{N,S<:NTuple{N}}
+    t::S
+end
+let mi = T26321{3,NTuple{3,Int}}((1,2,3)), mf = T26321{3,NTuple{3,Float64}}((1.0,2.0,3.0))
+    J = T26321{3,S} where S<:(Tuple{T,T,T} where T)
+    @test typejoin(typeof(mi),typeof(mf)) == J
+    a = [mi, mf]
+    @test a[1] === mi
+    @test a[2] === mf
+    @test eltype(a) == J
+    @test a isa Vector{<:T26321{3}}
+end
+
 # promote_typejoin returns a Union only with Nothing/Missing combined with concrete types
 for T in (Nothing, Missing)
     @test Base.promote_typejoin(Int, Float64) === Real
@@ -6015,4 +6029,4 @@ g25907b(x) = x[1]::Complex
 @test g25907b(Union{Complex{Int}, Complex{UInt}, Nothing}[1im]) === 1im
 
 #issue #26363
-@test eltype(Ref(Float64(1))) === Float64
\ No newline at end of file
+@test eltype(Ref(Float64(1))) === Float64