diff --git a/be/src/runtime/sorter.cc b/be/src/runtime/sorter.cc
index b8182e2d0..67603731f 100644
--- a/be/src/runtime/sorter.cc
+++ b/be/src/runtime/sorter.cc
@@ -1006,9 +1006,11 @@ bool Sorter::Run::ConvertOffsetsToPtrs(Tuple* tuple) {
       var_len_blocks_[var_len_blocks_index_]->buffer();
 
   const vector<SlotDescriptor*>& string_slots = sort_tuple_desc_->string_slots();
+  int num_non_null_string_slots = 0;
   for (int i = 0; i < string_slots.size(); ++i) {
     SlotDescriptor* slot_desc = string_slots[i];
     if (tuple->IsNull(slot_desc->null_indicator_offset())) continue;
+    ++num_non_null_string_slots;
 
     DCHECK(slot_desc->type().IsVarLenStringType());
     StringValue* value = reinterpret_cast<StringValue*>(
@@ -1026,7 +1028,9 @@ bool Sorter::Run::ConvertOffsetsToPtrs(Tuple* tuple) {
       DCHECK_LE(block_index, var_len_blocks_.size());
       DCHECK_EQ(block_index, var_len_blocks_index_ + 1);
       DCHECK_EQ(block_offset, 0); // The data is the first thing in the next block.
-      DCHECK_EQ(i, 0); // Var len data for tuple shouldn't be split across blocks.
+      // This must be the first slot with var len data for the tuple. Var len data
+      // for tuple shouldn't be split across blocks.
+      DCHECK_EQ(num_non_null_string_slots, 1);
       return false;
     }
 
diff --git a/testdata/workloads/functional-query/queries/QueryTest/single-node-large-sorts.test b/testdata/workloads/functional-query/queries/QueryTest/single-node-large-sorts.test
index 8000ad3c9..74b7eee6e 100644
--- a/testdata/workloads/functional-query/queries/QueryTest/single-node-large-sorts.test
+++ b/testdata/workloads/functional-query/queries/QueryTest/single-node-large-sorts.test
@@ -29,6 +29,38 @@ STRING,STRING,STRING
 'Faaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa','',''
 'Faaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa','',''
 ---- RUNTIME_PROFILE
-row_regex: .* TotalMergesPerformed: [^0] .*
-row_regex: .* SpilledRuns: [^0] .*
+row_regex: .* TotalMergesPerformed: [^0].*
+row_regex: .* SpilledRuns: [^0].*
+====
+---- QUERY
+# Regression test for IMPALA-5554: first string column in sort tuple is null
+# on boundary of spilled block. Test does two sorts with a NULL and non-NULL
+# string column in both potential orders.
+set max_block_mgr_memory=50m;
+select *
+from (
+  select *, first_value(col) over (order by sort_col) fv
+  from (
+    select concat(l_linestatus, repeat('a', 63)) sort_col, if(l_returnflag = 'foo', l_returnflag, NULL) col
+    from tpch_parquet.lineitem limit 100000
+    union all
+    select if(l_returnflag = 'foo', l_returnflag, NULL) sort_col, concat(l_linestatus, repeat('a', 63)) col
+    from tpch_parquet.lineitem) q limit 100000
+  ) q2
+limit 10
+---- TYPES
+STRING,STRING,STRING
+---- RESULTS
+'Faaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa','NULL','NULL'
+'Faaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa','NULL','NULL'
+'Faaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa','NULL','NULL'
+'Faaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa','NULL','NULL'
+'Faaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa','NULL','NULL'
+'Faaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa','NULL','NULL'
+'Faaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa','NULL','NULL'
+'Faaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa','NULL','NULL'
+'Faaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa','NULL','NULL'
+'Faaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa','NULL','NULL'
+---- RUNTIME_PROFILE
+row_regex: .* SpilledRuns: [^0].*
 ====