The price of Brent crude surged above $56 a barrel before easing slightly, reports the BBC.
Syria has limited oil production, but its location in the Middle East and alliances with big oil producers raised worries about a spreading conflict that could disrupt crude shipments.
European markets showed slight falls, with London’s FTSE 100 opening lower.
Shortly after the start of trading, it was down 0.03 per cent at 7,301.24.
Other asset classes seen as havens in times of trouble made gains. Gold prices were up 1.25 per cent at $1,253.75 an ounce.
The dollar’s performance was mixed, falling slightly against the dollar, sterling and yen, but holding its value against many other currencies.
In Asian markets, energy shares rose as a result of the airstrike, giving a boost to Japan’s Nikkei index, which closed up 0.36 per cent at 18,664.
Analysts said the market impact of the attacks was likely to be short-lived, since the US had described it as a “one-off”.
“It was a knee-jerk reaction because markets are starting to come back a little, as it doesn’t seem like there will be further retaliation coming,” said Christoffer Moltke-Leth at Saxo Capital Markets in Singapore.