Information and knowledge of sexual and reproductive health and rights (SRHR) plays a crucial role in promoting safe sexual practices among young migrants. We aimed to assess the sociodemographic factors of migrants associated with knowledge of condoms and the prevention, treatment, and transmission of HIV to highlight the need for SRHR information, including comprehensive sexual health education. A cross-sectional survey was conducted (2018-2019) among migrants at Swedish language schools and high schools across Sweden. The survey included questions about knowledge of condom use for preventing pregnancy and HIV treatment and transmission. Descriptive statistics were calculated, and multivariable logistic regression analyses were performed to assess the responses to the knowledge questions and sociodemographic characteristics. Out of 3430 respondents (median age: 35, interquartile range: 20), approximately 39% were unaware that condoms can prevent unplanned pregnancies. Only 58% of the respondents knew that condoms reduce the risk of contracting HIV. About 77% were unaware of HIV treatment, and 52% reported not knowing that a woman with HIV could transmit the virus to her baby during pregnancy or breastfeeding. Incorrect knowledge about condom use to prevent unwanted pregnancy was associated with several factors: younger age (15-19 years) adjusted odds ratio (aOR) 1.35; 95% confidence interval (CI), 1.02-1.79); female respondents (aOR: 1.68; 95% CI 1.36-2.07); lack of previous sexual health education (aOR: 2.57; 95% CI 2.11-3.13); low level of education (aOR: 1.30; 95% CI 1.04-1.61). Originating from the Americas, European, or sub-Saharan African regions was associated with a 34-42% decreased likelihood of incorrect knowledge that condoms can reduce the risk of HIV infection compared to respondents from the Middle East and North Africa (MENA). More than half (64%) of respondents reported needing more SRHR information. We found significant knowledge gaps on HIV and condom use for preventing pregnancy among migrants in Sweden. Comprehensive sexual health education in language schools, along with information to newly arrived migrants from diverse regional backgrounds and targeted sexual health services to younger individuals, women, and those who lack sexual health education, are needed to address these information gaps and provide crucial SRHR education and information.