West Yorkshire Police were called to an address off Malvern Road on Monday night, after receiving a call of concern about a dispute at the property.
A Knottingley man, aged 38, was arrested on suspicion of exploitation and a 42-year-old man from Slough was arrested on suspicion of facilitating the travel of another person with a view to exploitation.
Two adult women and a man were safeguarded from the property and are now being cared for by authorities.
Police say they are continuing to investigate the incident and safeguard the victims involved.
The arrests came a day before International Trafficking Prevention Day, intended to raise awareness of trafficking and the signs to look out for.
Detective Inspector Phil Davis, of Wakefield District CID, said: "We are continuing our enquiries into this incident after arresting two men in Knottingley last night following a call of concern about an address there.
“The victims are all being supported by partner agencies and the men remain in custody after being arrested on suspicion of human trafficking related offences."
Figures show there were 121 reports of modern day slavery made by West Yorkshire Police in 2018 - a 40 per cent increase on the previous 12 months.
In an unconnected incident, a man from West Yorkshire has bravely opened up about how he was a victim of slavery for 15 years.
Speaking about human trafficking, Mark Burns-Williamson, West Yorkshire's Police and Crime Commissioner (PCC) said: "Our communities continue to have a key role to play in stopping this from happening. We need you to report any suspicions, no matter how small, to the Modern Slavery Helpline on 08000 121 700 or to the police.
"General indicators of human trafficking or modern slavery can include signs of physical or psychological abuse, fear of authorities, irregular activity at homes or addresses, poor living conditions and working long hours for little or no pay.
"By reporting suspicions you could be saving a lives."