diff --git a/core/bash_impl.py b/core/bash_impl.py
index 48d552109a..83fa2604be 100644
--- a/core/bash_impl.py
+++ b/core/bash_impl.py
@@ -322,6 +322,27 @@ def SparseArray_SetElement(sparse_val, index, s):
     return 0
 
 
+def SparseArray_UnsetElement(sparse_val, index):
+    # type: (value.SparseArray, mops.BigInt) -> int
+    """A non-zero return value represents an error code. If this
+    function returns 1, the specified index is out of range.
+
+    """
+
+    index, ok = _SparseArray_CanonicalizeIndex(sparse_val, index)
+    if not ok:
+        return 1  # error_code: out-of-range index
+    mylib.dict_erase(sparse_val.d, index)
+
+    # update max_index
+    if mops.Equal(index, sparse_val.max_index):
+        sparse_val.max_index = mops.MINUS_ONE
+        for index in sparse_val.d:
+            if mops.Greater(index, sparse_val.max_index):
+                sparse_val.max_index = index
+    return 0
+
+
 def SparseArray_ToStrForShellPrint(sparse_val):
     # type: (value.SparseArray) -> str
 
diff --git a/core/state.py b/core/state.py
index 0ece2292ac..c7f87dbe6c 100644
--- a/core/state.py
+++ b/core/state.py
@@ -2288,6 +2288,15 @@ def Unset(self, lval, which_scopes):
                         raise error.Runtime(
                             "%s[%d]: Index is out of bounds for array of length %d"
                             % (var_name, lval.index, n))
+                elif val.tag() == value_e.SparseArray:
+                    val = cast(value.SparseArray, UP_val)
+                    error_code = bash_impl.SparseArray_UnsetElement(
+                        val, mops.IntWiden(lval.index))
+                    if error_code == 1:
+                        big_length = bash_impl.SparseArray_Length(val)
+                        raise error.Runtime(
+                            "%s[%d]: Index is out of bounds for array of length %s"
+                            % (var_name, lval.index, mops.ToStr(big_length)))
                 else:
                     raise error.Runtime("%r isn't an array" % var_name)
 
diff --git a/spec/ble-idioms.test.sh b/spec/ble-idioms.test.sh
index f568b8b1a5..9d6dd6de1b 100644
--- a/spec/ble-idioms.test.sh
+++ b/spec/ble-idioms.test.sh
@@ -534,5 +534,77 @@ sp1+=(2)
 ## STDERR:
 + sp1+=(2)
 ## END
+
 ## N-I bash/zsh/mksh/ash STDERR:
 ## END
+
+
+#### SparseArray: unset -v a[i]
+case $SH in bash|zsh|mksh|ash) exit ;; esac
+
+a=({1..9})
+var a = _a2sp(a)
+
+declare -p a
+unset -v "a[1]"
+declare -p a
+unset -v "a[9]"
+declare -p a
+unset -v "a[0]"
+declare -p a
+
+## STDOUT:
+declare -a a=([0]=1 [1]=2 [2]=3 [3]=4 [4]=5 [5]=6 [6]=7 [7]=8 [8]=9)
+declare -a a=([0]=1 [2]=3 [3]=4 [4]=5 [5]=6 [6]=7 [7]=8 [8]=9)
+declare -a a=([0]=1 [2]=3 [3]=4 [4]=5 [5]=6 [6]=7 [7]=8 [8]=9)
+declare -a a=([2]=3 [3]=4 [4]=5 [5]=6 [6]=7 [7]=8 [8]=9)
+## END
+
+## N-I bash/zsh/mksh/ash STDOUT:
+## END
+
+
+#### SparseArray: unset -v a[i] with out-of-bound negative index
+case $SH in bash|zsh|mksh|ash) exit ;; esac
+
+a=(1)
+var a = _a2sp(a)
+
+unset -v "a[-2]"
+unset -v "a[-3]"
+
+## status: 1
+## STDOUT:
+## END
+## STDERR:
+  unset -v "a[-2]"
+           ^
+[ stdin ]:6: a[-2]: Index is out of bounds for array of length 1
+  unset -v "a[-3]"
+           ^
+[ stdin ]:7: a[-3]: Index is out of bounds for array of length 1
+## END
+
+## N-I bash/zsh/mksh/ash status: 0
+## N-I bash/zsh/mksh/ash STDERR:
+## END
+
+
+#### SparseArray: unset -v a[i] for max index
+case $SH in bash|zsh|mksh|ash) exit ;; esac
+
+a=({1..9})
+unset -v 'a[-1]'
+a[-1]=x
+declare -p a
+unset -v 'a[-1]'
+a[-1]=x
+declare -p a
+
+## STDOUT:
+declare -a a=(1 2 3 4 5 6 7 x)
+declare -a a=(1 2 3 4 5 6 x)
+## END
+
+## N-I bash/zsh/mksh/ash STDOUT:
+## END