AirHint found the following cheapest return flights from Chicago (ORD) to Lisbon (LIS) in May 2026 (see full year).

Return flights

11 May - 21 May	British Airways
11 May - 20 May	Iberia
03 May - 20 May	Iberia
03 May - 09 May	TAP	direct
01 May - 09 May	TAP	direct
10 May - 20 May	British Airways
13 May - 22 May	Finnair
10 May - 20 May	TAP	direct
01 May - 08 May	TAP	direct
03 May - 20 May	TAP	direct
18 May - 12 Jun	Iberia
30 May - 04 Jun	TAP
30 May - 04 Jun	TAP	direct
26 May - 02 Jun	TAP

Also check the deals for one-way flights from Chicago to Lisbon in May.

The deals are updated regularly. The prices may go up as tickets are purchased by other travellers. Only the cheapest flights are offered. Select a price to book and secure these cheap prices.

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Cheapest return flights from Chicago to Lisbon in May from 428€

Return flights