Papua New Guinea crumbled to 53 all out as Scotland's 16-year-old leg-spinner Abtaha Maqsood (2-9) and 18-year-old seamer Kirstie Gordon (2-10) starred.
The Wildcats reached their target in 15.4 overs for the loss of two wickets, with Kari Anderson unbeaten on 24.
Bangladesh are Scotland's opposition on Sunday in their next Group A match.
Gordon told the Cricket Scotland website: "I'm really pleased with how I bowled. A really good first wicket and from then the wickets kept falling for the team.
"It is a massive game against Bangladesh. They are a full member, so we know they are going to be tougher opposition."
In Saturday's other Group A game, Bangladesh beat hosts Thailand, while in Group B, Ireland and Zimbabwe saw off the Netherlands and China respectively.
The top two teams in the eight-strong qualifying tournament will progress to next year's Women's World T20 in India.
Scotland defeated Papua New Guinea by eight wickets in their first match of the ICC Women's World Twenty20 Qualifier in Bangkok, Thailand.