diff --git a/Project.toml b/Project.toml
index 1177da1..d1c03f7 100644
--- a/Project.toml
+++ b/Project.toml
@@ -1,7 +1,7 @@
 name = "KroneckerArrays"
 uuid = "05d0b138-81bc-4ff7-84be-08becefb1ccc"
 authors = ["ITensor developers <support@itensor.org> and contributors"]
-version = "0.1.20"
+version = "0.1.21"
 
 [deps]
 Adapt = "79e6a3ab-5dfb-504d-930d-738a2a938a0e"
@@ -23,7 +23,7 @@ KroneckerArraysBlockSparseArraysExt = ["BlockArrays", "BlockSparseArrays"]
 [compat]
 Adapt = "4.3.0"
 BlockArrays = "1.6"
-BlockSparseArrays = "0.7.20"
+BlockSparseArrays = "0.7.21"
 DerivableInterfaces = "0.5.0"
 DiagonalArrays = "0.3.5"
 FillArrays = "1.13.0"
diff --git a/ext/KroneckerArraysBlockSparseArraysExt/KroneckerArraysBlockSparseArraysExt.jl b/ext/KroneckerArraysBlockSparseArraysExt/KroneckerArraysBlockSparseArraysExt.jl
index 114674e..9fa1018 100644
--- a/ext/KroneckerArraysBlockSparseArraysExt/KroneckerArraysBlockSparseArraysExt.jl
+++ b/ext/KroneckerArraysBlockSparseArraysExt/KroneckerArraysBlockSparseArraysExt.jl
@@ -3,7 +3,11 @@ module KroneckerArraysBlockSparseArraysExt
 using BlockArrays: Block
 using BlockSparseArrays: BlockIndexVector, GenericBlockIndex
 using KroneckerArrays: CartesianPair, CartesianProduct
-function Base.getindex(b::Block, I1::CartesianPair, Irest::CartesianPair...)
+function Base.getindex(
+  b::Block,
+  I1::Union{CartesianPair,CartesianProduct},
+  Irest::Union{CartesianPair,CartesianProduct}...,
+)
   return GenericBlockIndex(b, (I1, Irest...))
 end
 function Base.getindex(b::Block, I1::CartesianProduct, Irest::CartesianProduct...)
diff --git a/src/fillarrays/kroneckerarray.jl b/src/fillarrays/kroneckerarray.jl
index db51fc9..fc40ef7 100644
--- a/src/fillarrays/kroneckerarray.jl
+++ b/src/fillarrays/kroneckerarray.jl
@@ -22,6 +22,7 @@ const KroneckerSquareEye{T,A<:AbstractMatrix{T},B<:SquareEye{T}} = KroneckerMatr
 const SquareEyeSquareEye{T,A<:SquareEye{T},B<:SquareEye{T}} = KroneckerMatrix{T,A,B}
 
 _getindex(a::Eye, I1::Colon, I2::Colon) = a
+_view(a::Eye, I1::Colon, I2::Colon) = a
 
 # Like `adapt` but preserves `Eye`.
 _adapt(to, a::Eye) = a
diff --git a/src/kroneckerarray.jl b/src/kroneckerarray.jl
index 636c1cd..94d601a 100644
--- a/src/kroneckerarray.jl
+++ b/src/kroneckerarray.jl
@@ -178,6 +178,17 @@ end
 # Fix ambigiuity error.
 Base.getindex(a::KroneckerArray{<:Any,0}) = arg1(a)[] * arg2(a)[]
 
+# Allow customizing for `FillArrays.Eye`.
+_view(a::AbstractArray, I...) = view(a, I...)
+function Base.view(a::KroneckerArray{<:Any,N}, I::Vararg{CartesianProduct,N}) where {N}
+  return _view(arg1(a), arg1.(I)...) ⊗ _view(arg2(a), arg2.(I)...)
+end
+function Base.view(a::KroneckerArray{<:Any,N}, I::Vararg{CartesianPair,N}) where {N}
+  return _view(arg1(a), arg1.(I)...) ⊗ _view(arg2(a), arg2.(I)...)
+end
+# Fix ambigiuity error.
+Base.view(a::KroneckerArray{<:Any,0}) = _view(arg1(a)) * _view(arg2(a))
+
 function Base.:(==)(a::KroneckerArray, b::KroneckerArray)
   return arg1(a) == arg1(b) && arg2(a) == arg2(b)
 end
diff --git a/test/Project.toml b/test/Project.toml
index 9f9c5a9..16b4265 100644
--- a/test/Project.toml
+++ b/test/Project.toml
@@ -21,7 +21,7 @@ TestExtras = "5ed8adda-3752-4e41-b88a-e8b09835ee3a"
 Adapt = "4"
 Aqua = "0.8"
 BlockArrays = "1.6"
-BlockSparseArrays = "0.7.19"
+BlockSparseArrays = "0.7.21"
 DerivableInterfaces = "0.5"
 DiagonalArrays = "0.3.7"
 FillArrays = "1"
diff --git a/test/test_basics.jl b/test/test_basics.jl
index c8fa835..0fe2ef3 100644
--- a/test/test_basics.jl
+++ b/test/test_basics.jl
@@ -11,6 +11,8 @@ using KroneckerArrays:
   CartesianProductUnitRange,
   ⊗,
   ×,
+  arg1,
+  arg2,
   cartesianproduct,
   cartesianrange,
   kron_nd,
@@ -67,8 +69,8 @@ elts = (Float32, Float64, ComplexF32, ComplexF64)
   @test x == y
 
   a = @constinferred(randn(elt, 2, 2) ⊗ randn(elt, 3, 3))
-  b = randn(elt, 2, 2) ⊗ randn(elt, 3, 3)
-  c = a.a ⊗ b.b
+  b = @constinferred(randn(elt, 2, 2) ⊗ randn(elt, 3, 3))
+  c = @constinferred(a.a ⊗ b.b)
   @test a isa KroneckerArray{elt,2,typeof(a.a),typeof(a.b)}
   @test similar(typeof(a), (2, 3)) isa Matrix{elt}
   @test size(similar(typeof(a), (2, 3))) == (2, 3)
@@ -101,6 +103,14 @@ elts = (Float32, Float64, ComplexF32, ComplexF64)
   @test tr(a) ≈ tr(collect(a))
   @test norm(a) ≈ norm(collect(a))
 
+  # Views
+  a = @constinferred(randn(elt, 2, 2) ⊗ randn(elt, 3, 3))
+  b = @constinferred(view(a, (1:2) × (2:3), (1:2) × (2:3)))
+  @test arg1(b) === view(arg1(a), 1:2, 1:2)
+  @test arg1(b) == arg1(a)[1:2, 1:2]
+  @test arg2(b) === view(arg2(a), 2:3, 2:3)
+  @test arg2(b) == arg2(a)[2:3, 2:3]
+
   # Broadcasting
   a = randn(elt, 2, 2) ⊗ randn(elt, 3, 3)
   style = KroneckerStyle(BroadcastStyle(typeof(a.a)), BroadcastStyle(typeof(a.b)))
diff --git a/test/test_blocksparsearrays.jl b/test/test_blocksparsearrays.jl
index 1d37e15..bd88d9d 100644
--- a/test/test_blocksparsearrays.jl
+++ b/test/test_blocksparsearrays.jl
@@ -1,5 +1,5 @@
 using Adapt: adapt
-using BlockArrays: Block, BlockRange
+using BlockArrays: Block, BlockRange, mortar
 using BlockSparseArrays:
   BlockSparseArray, BlockSparseMatrix, blockrange, blocksparse, blocktype
 using FillArrays: Eye, SquareEye
@@ -38,22 +38,69 @@ arrayts = (Array, JLArray)
   @test a[Block(1, 2)] == dev(zeros(elt, 2, 3) ⊗ zeros(elt, 2, 3))
   @test a[Block(1, 2)] isa valtype(d)
 
+  # Slicing
+  r = blockrange([2 × 2, 3 × 3])
+  d = Dict(
+    Block(1, 1) => dev(randn(elt, 2, 2) ⊗ randn(elt, 2, 2)),
+    Block(2, 2) => dev(randn(elt, 3, 3) ⊗ randn(elt, 3, 3)),
+  )
+  a = dev(blocksparse(d, r, r))
+  @test a[Block(2, 2)[(2:3) × (2:3), (2:3) × (2:3)]] ==
+    a[Block(2, 2)][(2:3) × (2:3), (2:3) × (2:3)]
+  @test a[Block(2, 2)[(:) × (2:3), (:) × (2:3)]] == a[Block(2, 2)][(:) × (2:3), (:) × (2:3)]
+  @test_broken a[Block(2, 2)][(1:2) × (2:3), (:) × (2:3)]
+
+  # Slicing
+  r = blockrange([2 × 2, 3 × 3])
+  d = Dict(
+    Block(1, 1) => dev(randn(elt, 2, 2) ⊗ randn(elt, 2, 2)),
+    Block(2, 2) => dev(randn(elt, 3, 3) ⊗ randn(elt, 3, 3)),
+  )
+  a = dev(blocksparse(d, r, r))
+  i1 = Block(1)[(1:2) × (1:2)]
+  i2 = Block(2)[(2:3) × (2:3)]
+  I = mortar([i1, i2])
+  b = @view a[I, I]
+  b′ = copy(b)
+  @test b[Block(2, 2)] == b′[Block(2, 2)] == a[Block(2, 2)[(2:3) × (2:3), (2:3) × (2:3)]]
+  @test_broken b[Block(1, 2)]
+
+  # Slicing
+  r = blockrange([2 × 2, 3 × 3])
+  d = Dict(
+    Block(1, 1) => dev(randn(elt, 2, 2) ⊗ randn(elt, 2, 2)),
+    Block(2, 2) => dev(randn(elt, 3, 3) ⊗ randn(elt, 3, 3)),
+  )
+  a = dev(blocksparse(d, r, r))
+  i1 = Block(1)[(1:2) × (1:2)]
+  i2 = Block(2)[(2:3) × (2:3)]
+  I = [i1, i2]
+  b = @view a[I, I]
+  b′ = copy(b)
+  @test b[Block(2, 2)] == b′[Block(2, 2)] == a[Block(2, 2)[(2:3) × (2:3), (2:3) × (2:3)]]
+  @test_broken b[Block(1, 2)]
+
+  # Matrix multiplication
   b = a * a
   @test typeof(b) === typeof(a)
   @test Array(b) ≈ Array(a) * Array(a)
 
+  # Addition (mapping, broadcasting)
   b = a + a
   @test typeof(b) === typeof(a)
   @test Array(b) ≈ Array(a) + Array(a)
 
+  # Scaling (mapping, broadcasting)
   b = 3a
   @test typeof(b) === typeof(a)
   @test Array(b) ≈ 3Array(a)
 
+  # Dividing (mapping, broadcasting)
   b = a / 3
   @test typeof(b) === typeof(a)
   @test Array(b) ≈ Array(a) / 3
 
+  # Norm
   @test norm(a) ≈ norm(Array(a))
 
   if arrayt === Array
@@ -102,6 +149,48 @@ end
   @test a[Block(1, 2)] == dev(Eye(2, 3) ⊗ zeros(elt, 2, 3))
   @test a[Block(1, 2)] isa valtype(d)
 
+  # Slicing
+  r = blockrange([2 × 2, 3 × 3])
+  d = Dict(
+    Block(1, 1) => dev(Eye{elt}(2, 2) ⊗ randn(elt, 2, 2)),
+    Block(2, 2) => dev(Eye{elt}(3, 3) ⊗ randn(elt, 3, 3)),
+  )
+  a = dev(blocksparse(d, r, r))
+  @test a[Block(2, 2)[(2:3) × (2:3), (2:3) × (2:3)]] ==
+    a[Block(2, 2)][(2:3) × (2:3), (2:3) × (2:3)]
+  @test a[Block(2, 2)[(:) × (2:3), (:) × (2:3)]] == a[Block(2, 2)][(:) × (2:3), (:) × (2:3)]
+  @test_broken a[Block(2, 2)][(1:2) × (2:3), (:) × (2:3)]
+
+  # Slicing
+  r = blockrange([2 × 2, 3 × 3])
+  d = Dict(
+    Block(1, 1) => dev(Eye{elt}(2, 2) ⊗ randn(elt, 2, 2)),
+    Block(2, 2) => dev(Eye{elt}(3, 3) ⊗ randn(elt, 3, 3)),
+  )
+  a = dev(blocksparse(d, r, r))
+  i1 = Block(1)[(1:2) × (1:2)]
+  i2 = Block(2)[(2:3) × (2:3)]
+  I = mortar([i1, i2])
+  b = @view a[I, I]
+  @test b[Block(2, 2)] == a[Block(2, 2)[(2:3) × (2:3), (2:3) × (2:3)]]
+  @test_broken copy(b)
+  @test_broken b[Block(1, 2)]
+
+  # Slicing
+  r = blockrange([2 × 2, 3 × 3])
+  d = Dict(
+    Block(1, 1) => dev(Eye{elt}(2, 2) ⊗ randn(elt, 2, 2)),
+    Block(2, 2) => dev(Eye{elt}(3, 3) ⊗ randn(elt, 3, 3)),
+  )
+  a = dev(blocksparse(d, r, r))
+  i1 = Block(1)[(1:2) × (1:2)]
+  i2 = Block(2)[(2:3) × (2:3)]
+  I = [i1, i2]
+  b = @view a[I, I]
+  @test b[Block(2, 2)] == a[Block(2, 2)[(2:3) × (2:3), (2:3) × (2:3)]]
+  @test_broken copy(b)
+  @test_broken b[Block(1, 2)]
+
   b = @constinferred a * a
   @test typeof(b) === typeof(a)
   @test Array(b) ≈ Array(a) * Array(a)
diff --git a/test/test_fillarrays.jl b/test/test_fillarrays.jl
index f852ef9..62e0234 100644
--- a/test/test_fillarrays.jl
+++ b/test/test_fillarrays.jl
@@ -1,9 +1,10 @@
 using DerivableInterfaces: zero!
 using FillArrays: Eye, Zeros
-using KroneckerArrays: KroneckerArrays, KroneckerArray, ⊗
+using KroneckerArrays: KroneckerArrays, KroneckerArray, ⊗, ×, arg1, arg2
 using LinearAlgebra: det, norm, pinv
 using StableRNGs: StableRNG
 using Test: @test, @test_throws, @testset
+using TestExtras: @constinferred
 
 @testset "FillArrays.Eye" begin
   MATRIX_FUNCTIONS = KroneckerArrays.MATRIX_FUNCTIONS
@@ -18,12 +19,26 @@ using Test: @test, @test_throws, @testset
   @test 2a == Eye(2) ⊗ (2a.b)
   @test a * a == Eye(2) ⊗ (a.b * a.b)
 
+  # Views
+  a = @constinferred(Eye(2) ⊗ randn(3, 3))
+  b = @constinferred(view(a, (:) × (2:3), (:) × (2:3)))
+  @test arg1(b) === Eye(2)
+  @test arg2(b) === view(arg2(a), 2:3, 2:3)
+  @test arg2(b) == arg2(a)[2:3, 2:3]
+
   a = randn(3, 3) ⊗ Eye(2)
   @test size(a) == (6, 6)
   @test a + a == (2a.a) ⊗ Eye(2)
   @test 2a == (2a.a) ⊗ Eye(2)
   @test a * a == (a.a * a.a) ⊗ Eye(2)
 
+  # Views
+  a = @constinferred(randn(3, 3) ⊗ Eye(2))
+  b = @constinferred(view(a, (2:3) × (:), (2:3) × (:)))
+  @test arg1(b) === view(arg1(a), 2:3, 2:3)
+  @test arg1(b) == arg1(a)[2:3, 2:3]
+  @test arg2(b) === Eye(2)
+
   # similar
   a = Eye(2) ⊗ randn(3, 3)
   for a′ in (